Acute Stroke Care: A Manual from the University of Texas - Houston Stroke Team (Cambridge Pocket Clinicians)

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Author: Ken Uchino | Jennifer Pary | James Grotta

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Acute Stroke Care You have just encountered a possible stroke patient. You ask yourself, what should I do first? How do I know it is a stroke? Is it too late to reverse the damage? How do I do the right things in the right order? This book will help you answer these critical questions. It provides practical advice on the care of stroke patients in a range of acute settings. As new and effective treatments become available, and designated stroke centers are created, this guidebook will help inform the healthcare professionals responsible for delivering care. The content is arranged in chronological order, covering the things to consider in assessing and treating the patient in the emergency department, the stroke unit, and then on transfer to a rehabilitation facility. All types of stroke are covered. A comprehensive set of appendices contain useful reference information including dosing algorithms, conversion factors, and stroke scales. Ken Uchino is an Assistant Professor of Neurology at the University of Pittsburgh School of Medicine and a Vascular Neurologist at the University of Pittsburgh Medical Center Strohe Institute. Jennifer Pary is a Vascular Neurologist at the Center for Neurosciences, Orthopedics and Spine, Dakota Dunes, South Dakota. James Grotta is Professor and Chairman in the Department of Neurology, University of Texas Medical School at Houston.

Cambridge Pocket Clinicians Cambridge Pocket Clinicians provide practical, portable, notebased guidance for medical trainees, junior doctors, residents, and those from outside the field seeking an accessible overview. Written making maximum use of lists, bullet points, summary boxes and algorithms, they allow the reader fast and ready access to essential information.

Acute Stroke Care A Manual from the University of Texas-Houston Stroke Team

Ken Uchino, M.D. Jennifer K. Pary, M.D. James C. Grotta, M.D.

CAMBRIDGE UNIVERSITY PRESS

Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, São Paulo Cambridge University Press The Edinburgh Building, Cambridge CB2 8RU, UK Published in the United States of America by Cambridge University Press, New York www.cambridge.org Information on this title: www.cambridge.org/9780521674942 © K. Uchino, J. Pary and J. Grotta 2007 This publication is in copyright. Subject to statutory exception and to the provision of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press. First published in print format 2007 eBook (EBL) ISBN-13 978-0-511-28888-3 ISBN-10 0-511-28888-3 eBook (EBL) ISBN-13 ISBN-10

paperback 978-0-521-67494-2 paperback 0-521-67494-8

Cambridge University Press has no responsibility for the persistence or accuracy of urls for external or third-party internet websites referred to in this publication, and does not guarantee that any content on such websites is, or will remain, accurate or appropriate. Every effort has been made in preparing this publication to provide accurate and up-todate information which is in accord with accepted standards and practice at the time of publication. Although case histories are drawn fromactual cases, every effort has been made to disguise the identities of the individuals involved. Nevertheless, the authors, editors and publishers can make no warranties that the information contained herein is totally free from error, not least because clinical standards are constantly changing through research and regulation. The authors, editors and publishers therefore disclaim all liability for direct or consequential damages resulting from the use of material contained in this publication. Readers are strongly advised to pay careful attention to information provided by the manufacturer of any drugs or equipment that they plan to use.

Contents

Preface

page xi

List of abbreviations

xiv

1 Stroke in the emergency department

1

Is this a stroke?

1

What type of stroke?

6

2 What to do first

8

Airway – breathing – circulation (ABCs)

8

What was the time of onset?

9

How bad are the symptoms now?

10

Do a non-contrast head CT

10

If the CT shows no blood, try to get the artery open

11

Recommended diagnostic evaluation

11

3 Ischemic stroke

13

Definition

13

Etiology

13

Diagnosis

13

The four components of ischemic stroke care

14

v

vi

Contents

Acute therapy and optimization of neurological status

14

Etiological work-up for secondary prevention

22

Prevention of neurological deterioration or medical complications

26

Stroke recovery and rehabilitation

29

Ischemic stroke outcome

30

General timeline

32

4 TPA protocol

33

TPA indications

33

Strong contraindications

34

Relative contraindications

36

Procedure

38

Dose

39

Sample post-TPA orders

39

Risks vs. benefits of TPA

41

Unproven therapies

44

5 Neurological deterioration in acute ischemic stroke

48

Probable causes

48

Initial evaluation of patients with neurologic deterioration

49

Stroke enlargement

49

Drop in perfusion pressure

50

Recurrent stroke

50

Cerebral edema and mass effect

51

Hemorrhagic transformation

56

Metabolic disturbance

58

Seizure

58

Contents

vii

Symptom fluctuations without a good cause

59

The uncooperative patient

60

6 Ischemic stroke prevention: why we do the things we do

61

Investigations

61

Ischemic stroke prevention: general measures

65

Atrial fibrillation (A fib)

70

Carotid stenosis

74

Acute carotid occlusion

78

Lacunar strokes

79

Cervical arterial dissection

81

Patent foramen ovale

83

7 Transient ischemic attack (TIA)

85

Definition

85

Etiology

86

Presentation

86

Differential diagnosis

86

Clinical approach to a patient with suspected TIA

87

Prognosis after TIA

90

8 Intracerebral hemorrhage (ICH)

91

Definition

91

Etiology

92

Presentation

93

Diagnosis and evaluation

94

Management Prognosis and outcome

95 100

viii

Contents

9 Subarachnoid hemorrhage (SAH)

101

Definition

101

Epidemiology

101

Presentation

102

Diagnosis

102

Ruptured aneurysms: management

104

Prognosis

109

Admission sequence

109

Unruptured aneurysms

111

10 Organization of stroke care

114

Timely care

114

Stroke units

115

Stroke centers

116

Stroke teams

116

11 Rehabilitation

118

Secondary stroke prevention

119

Prevention of medical complications

119

Multidisciplinary rehabilitation team

119

Discharge planning

126

Appendix 1. Numbers and calculations

129

Appendix 2. IV TPA dosing chart

131

Appendix 3. Sample admission orders

133

Appendix 4. Sample discharge summary

139

Appendix 5. Stroke radiology

141

Contents

Appendix 6. Transcranial Doppler ultrasound (TCD)

157

Appendix 7. Heparin protocol

161

Appendix 8. Insulin protocol

163

Appendix 9. Medical complications

165

Appendix 10. Brainstem syndromes

170

Appendix 11. Cerebral arterial anatomy

173

Appendix 12. Stroke in the young and less common stroke diagnoses

175

Appendix 13. Brain death criteria

178

Appendix 14. Neurological scales

181

Recommended reading

200

References

203

ix

Preface

You have just been called to the emergency department to evaluate and treat a possible stroke patient. You ask yourself: What should I do first? How do I know it is a stroke? Is it too late to reverse the damage, and if not, how do I do it? How do I make sure that I do things correctly during the first day or so to prevent worsening? This handbook is designed to answer these real-life questions. As new and effective stroke treatments are now available, and the creation of designated stroke centers for optimal care of stroke patients is endorsed and put into practice, there is a need for a guidebook that will help enlarge and inform the group of healthcare professionals responsible for delivering this care. The handbook has been compiled from the day-to-day experiences of the Stroke Team at the University of Texas Medical School – Houston in caring for acute stroke patients on a dedicated in-patient stroke service. It describes the options and underlying rationale for making treatment decisions for stroke patients in the emergency department, stroke unit, neurological critical care unit, and pre-rehabilitation setting. It is evidence-based where evidence exists, but much of what is included reflects our best interpretation of what should be done in the absence of conclusive data.

xi

xii

Preface

It is intended as a practical guide to be used by medical students, house officers, and other clinicians with first-hand responsibility for the ‘‘nuts and bolts’’ care of these patients. The handbook has been arranged generally in chronological order, covering the things one should consider in assessing and treating the patient in the emergency department (ED), then the stroke unit, and then on discharge or transfer to a rehabilitation facility. Having dealt with the diagnosis of stroke and the essential first steps in the emergency department, we then consider the management of each type of stroke in turn. We begin with ischemic stroke, followed by separate chapters detailing several important issues in ischemic stroke management; the use of thrombolytic therapy, how to approach neurological deterioration, selecting appropriate secondary stroke prevention, and, finally, transient ischemic attack. Then we move on to intracerebral hemorrhage and subarachnoid hemorrhage, before ending chapters on how to organize stroke care and the principles of rehabilitation and stroke recovery. There is more detail in the ischemic stroke chapter because it represents the initial and most complex decision-making in the ED. When called to the ED to see an acute stroke patient, most often it will be an ischemic stroke, and since the therapy for this condition is most urgent, you should start by assuming it is an ischemic stroke. If, during your evaluation of the patient, you determine that the patient has a TIA or hemorrhage, then many of the same principles outlined in the ischemic stroke chapter also will apply, but you will find specific information for patients with TIA or hemorrhage in their appropriate chapters. The appendices contain useful reference information that is referred to in the text but is detailed and hard to remember, such as dosing algorithms and conversion factors, standing

Preface

orders, drug protocols, various stroke scales, and detailed description of imaging sequences and brainstem syndromes. * In the text, an asterisk marks where there is sufficient evidence to make a strong recommendation based on randomized trials or consensus statements. However, for most decisions, such data do not exist, and we have not hesitated to include our advice based on our collective experiences, and observations of where mistakes are frequently made, and we have emphasized by bold lettering some of those areas where there are particular important values or pieces of information that can help facilitate proper treatment and avoid errors. We emphasize that this is a manual for acute stroke diagnosis and treatment, and hence some disclaimers are needed for what this work does not cover. We presume the reader has a basic knowledge of neuroanatomy and vascular physiology, covered in medical and nursing school curricula. None of this is covered, though we provide a refresher for vascular anatomy in an appendix. Similarly, we presume the reader has a basic knowledge of the neurological examination and its common findings in stroke patients, covered in courses on physical diagnosis. Again, this is not covered, though we provide a review of some of the more rare brainstem syndromes in an appendix. Finally, we recognize that a detailed description of the epidemiology, pathology, and outcome of stroke and all of its subtypes, and even many aspects of its diagnosis, treatment, and prevention are left uncovered. For these, we refer the reader to standard excellent texts on cerebrovascular disease. We hope that this work will help the reader become more comfortable in dealing with the complexities of urgent decisionmaking, thereby increasing the number of medical personnel engaged in providing acute stroke care, with the end result of reducing the devastation caused by stroke in our society.

xiii

Abbreviations

xiv

ACA

anterior cerebral artery

ACE

angiotensin converting enzyme

AHA

American Heart Association

ARR

absolute risk reduction

ASA

American Stroke Association

AVM

arteriovenous malformation

CBC

complete blood count

CBV

cerebral blood volume

CEA

carotid endarterectomy

CN

cranial nerve

CPP

cerebral perfusion pressure

CSF

cerebrospinal fluid

CT

computed tomography

CTA

CT angiography

CUS

carotid ultrasound

DBP

diastolic blood pressure

DSA

digital subtraction angiography

DVT

deep venous thrombosis

ED

emergency department

EEG

electroencephalogram

EKG

electrocardiogram

FDA

Food and Drug Administration (USA)

FFP

fresh frozen plasma


GCS

Glasgow coma scale

HIT

heparin-induced thrombocytopenia

HITTS

heparin-induced thrombocytopenia with thrombotic syndrome

IA

intra-arterial

ICA

internal carotid artery

ICH

intracerebral hemorrhage

ICP

intracranial pressure

ICU

intensive care unit

IM

intramuscular

INR

international normalized ratio

IV

intravenous

IVH

intraventricular hemorrhage

LDL

low-density lipoprotein

LMN

lower motor neuron

LTAC

long-term acute care

MAP

mean arterial pressure

MCA

middle cerebral artery

MI

myocardial infarction

MRA

magnetic resonance angiogram

MRI

magnetic resonance imaging

NIH

National Institutes of Health

NIHSS

National Institutes of Health Stroke Scale

NINDS

National Institute of Neurological Disorders and Stroke

NNH

number needed to harm

NNT

number needed to treat

NPO

nil per os (nil by mouth)

OT

occupational therapy

PCA

posterior cerebral artery

PEG

percutaneous endoscopic gastrostomy

PFO

patent foramen ovale

xv


xvi

PO

per os (by mouth)

PT

physical therapy

PTT

partial thromboplastin time

RLS

right-to-left shunt

RRR

relative risk reduction

SAH

subarachnoid hemorrhage

SBP

systolic blood pressure

SC

subcutaneous

SNF

skilled nursing facility

ST

speech therapy

TCD

transcranial Doppler ultrasound

TEE

transesophageal echocardiogram

TIA

transient ischemic attack

TPA

tissue plasminogen activator

TTE

transthoracic echocardiogram

1 Stroke in the emergency department Stroke is the most common neurological emergency, and, because effective treatment is available that must be started within minutes, most acute neurological presentations should be assumed to be a stroke until proven otherwise by history, exam, or radiographic testing. Unfortunately, there is not a quick and easy laboratory or clinical test to determine for sure that the patient lying in front of you is having a stroke, so an accurate history and exam are essential.

n Is this a stroke? DEFINITION The term ‘‘stroke’’ usually refers either to a cerebral infarction or to non-traumatic cerebral hemorrhage. Depending on the population you are seeing (ethnicity, age, comorbidities) the ratio of infarcts to hemorrhages is about 4:1. As will be described in more detail in Chapter 3, cerebral infarcts can be caused by a number of pathological processes, but all end with an occlusion of a cerebral artery or vein. If the arterial occlusion results in a reduction of blood flow insufficient to cause death of tissue (infarction), it is termed ‘‘ischemia.’’

1

n n n n n n n n n n n n n n n n n n n n n n n n

2

Stroke in the emergency department

As will be described in more detail in Chapter 8, nontraumatic cerebral hemorrhages are caused by a number of pathological processes which all lead to bleeding into the brain parenchyma and ventricles. Bleeding into the subarachnoid space (Chapter 9) is usually caused by a ruptured aneurysm or vascular malformation. Other types of brain bleeding, for example into the subdural or epidural space, are usually traumatic and are not considered in this book.

PRESENTATION When taking the history, the most characteristic aspect of a cerebral infarct or hemorrhage is the abrupt onset, so be sure to get the exact flavor of the onset. It is also imperative to determine as precisely as possible the time of onset. The symptoms most often stay the same or improve somewhat over the next hours, but may worsen in a smooth or stuttering course. Ischemic strokes (but not hemorrhages) may rapidly resolve, but even if they resolve completely, they may recur after minutes to hours. The second characteristic historical aspect of cerebral infarcts is that the symptoms will usually fit the distribution of a single vascular territory. This is also the most important characteristic of the neurological exam in a patient with an infarct. Therefore, patients with an infarct will present with symptoms and signs in the middle, anterior, or posterior cerebral arteries, a penetrating artery (producing a ‘‘lacunar’’ syndrome), or the vertebral or basilar artery (see below). Parenchymal hemorrhages also occur in characteristic locations, and usually share the same symptom complex and signs as cerebral infarcts except that early decrease in level of consciousness, nausea and vomiting, headache, and accelerated hypertension are more common with hemorrhages.

Is this a stroke?

Subarachnoid hemorrhages classically present as a bursting very severe headache (‘‘the worst headache of my life’’), and are often accompanied by stiff neck, decreased consciousness, nausea and vomiting. Focal neurological signs are often absent; if present, they usually signify associated bleeding into the parenchyma.

Signs and symptoms characteristic of the various arterial territories .

Middle cerebral – contralateral loss of strength and sensation in the face, arm, and to a lesser extent leg. Aphasia if dominant hemisphere, neglect if non-dominant.

.

Anterior cerebral – contralateral loss of strength and sensation in the leg and to a lesser extent arm.

.

Posterior cerebral – contralateral visual field deficit. Possibly confusion and aphasia if dominant hemisphere.

.

Penetrating (lacunar syndrome) – contralateral weakness or sensory loss (usually not both) in face, arm, and leg. No aphasia, neglect, or visual loss. Possibly ataxia, dysarthria.

.

Vertebral (or posterior inferior cerebellar) – truncal ataxia, dysarthria, dysphagia, ipsilateral sensory loss on the face, and contralateral sensory loss below the neck.

.

Basilar – various combinations of limb ataxia, dysarthria, dysphagia, facial and limb weakness and sensory loss (may be bilateral), pupillary asymmetry, disconjugate gaze, visual field loss, decreased responsiveness.

DIAGNOSIS There is currently no 100% sensitive and specific test for cerebral infarction in the emergency department, so that the

3




4

diagnosis is usually made on the basis of a characteristic history, exam, presence of comorbidities, and the absence of seizures or other stroke mimics. CT scanning is usually negative in the first three hours, or shows only subtle signs that have low inter-observer reliability. If available, MR imaging, or detection of an occluded artery by transcranial Doppler or arteriography (by CT, MRI or intra-arterial catheterization), can be confirmatory. Parenchymal or subarachnoid hemorrhage, on the other hand, can be reliably detected by emergent CT scanning.

STROKE MIMICS All of the following may present similarly to a stroke. In all cases, the distinction can be made by an emergent MRI scan, which will show abnormal diffusion-weighted signal in most stroke cases, but not in mimics. .

Seizures. If a seizure has a focal onset in the brain, the patient may be left with weakness, numbness, speech, or vision problems for a period of time (usually less than 24 hours) after the seizure. Unlike the typical cerebral infarct, focal deficits after a seizure are often accompanied by lethargy and have a resolving course, but if the patient has had a seizure accompanying a stroke it is impossible to know for sure how much of the deficit the patient displays is due to each. This is why patients with seizures at onset are usually excluded from clinical trials of new stroke therapies.

.

Migraine. Patients may have unilateral weakness or numbness, visual changes, or speech disturbances associated with a migraine headache (‘‘complicated’’ or ‘‘complex’’ migraine). Also, patients with complicated migraine are at higher risk for stroke. In trying to make the distinction

Is this a stroke?

between complicated migraine and stroke, it is important to remember that because of the high prevalence of both migraine and stroke in the general population, it is dangerous to attribute the patient’s deficit to migraine just because the patient has a migraine history. The best rule of thumb is not to make the diagnosis of complicated migraine or migrainous stroke unless the patient has a history of previous complicated migraine events similar to the deficit displayed in the emergency department. .

Syncope. This is usually due to hypotension or a cardiac arrhythmia. Stroke rarely presents with syncope alone. Patients with vertebrobasilar insufficiency may have syncope, but there are usually other brainstem or cerebellar findings if syncope is part of the stroke presentation.

.

Hypoglycemia. Patients with low blood sugar may have symptoms that exactly mimic a stroke. The important thing is to check the blood sugar and, if low, correct it. If the symptoms do not resolve with correction of the hypoglycemia, the symptoms are probably from a stroke.

.

Metabolic encephalopathy. Patients may have confusion, slurred speech, or rarely aphasia with this condition. They usually do not have other prominent focal findings.

.

Drug overdose. Similar to metabolic encephalopathy.

.

Central nervous system tumor. The location of the tumor would determine the type of signs and symptoms seen. A tumor, unlike a stroke, usually does not present with sudden focal findings, unless accompanied by a seizure (see above).

.

Herpes simplex encephalitis (HSE). This infection tends predominantly to affect the temporal lobes, so patients may have signs of aphasia, hemiparesis or visual-field cuts. Onset can be rapid and in its early stages may mimic a stroke, but fever,

5




6

CSF pleocytosis, seizures and decreased level of consciousness are more prominent with HSE. .

Subdural hematoma. Depending on the location, this may cause contralateral weakness or numbness that may mimic a stroke. A CT scan can make this diagnosis, but the subdural, if small, may be subtle.

.

Peripheral compression neuropathy. This may cause weakness or numbness in a particular peripheral nerve distribution and is usually not sudden in onset.

.

Bell’s palsy (peripheral seventh nerve palsy). The important point here is that the forehead and eye closure are weak on the same side. One can have a stroke involving the pons and produce a peripheral seventh nerve palsy, but usually there are other signs and symptoms such as weakness, a gaze palsy, or ipsilateral sixth nerve palsy.

.

Benign paroxysmal positional vertigo (BPPV). This may cause vertigo, nausea, vomiting, and a sense of imbalance, usually with turning of the head in one direction. This characteristic syndrome is due to labyrinthine dysfunction and not stroke. However, as with syncope, the presence of any brainstem or cerebellar signs should alert one to the possibility of a stroke.

.

Conversion disorder. Patients may develop neurological signs or symptoms of weakness, numbness, or trouble talking that are manifestations of stress or a psychiatric illness. Always assume that your patient has a true neurologic illness first.

n What type of stroke? As discussed previously, there are two main types of stroke: ischemic and hemorrhagic. The majority of this book describes

What type of stroke?

the approach to either type of stroke, but there are specific chapters on ischemic stroke, TIA, ICH, and SAH: .

Ischemic stroke (Chapter 3).

.

Transient ischemic attack (Chapter 7).

.

Intracerebral hemorrhage (Chapter 8).

.

Subarachnoid hemorrhage (Chapter 9).

7


2 What to do first

The following initial measures apply to all stroke patients. They are necessary to stabilize and assess the patient, and prepare for definitive therapy. All current and, probably, future stroke therapies for both ischemic and hemorrhagic stroke are best implemented as fast as possible, so these things need to be done quickly. This is the general order to do things, but in reality, in order to speed the process, these measures are usually dealt with simultaneously. They are best addressed in the ED, where urgent care pathways for stroke should be established and part of the routine (see Chapter 10).

n Airway – breathing – circulation (ABCs) .

O2 via nasal cannula (routine oxygen delivery in ischemia might improve outcome).*

.

Intubation may be necessary if the patient shows arterial oxygen desaturation or cannot ‘‘protect’’ their airway from aspirating secretions. However, intubation means that the ability to monitor the neurological exam is lost. The best approach in such patients is to prepare to intubate immediately, but before doing so, take a moment to be sure the patient does not spontaneously improve or stabilize with

8

What was the time of onset?

good nursing care (suctioning, head position, etc.). Also, if needed, use sedating or paralyzing drugs with a short halflife, to allow for serial neurological exams. .

Consider putting the head of the bed flat. This can significantly help cerebral perfusion. The head of the bed may need to be elevated if airway protection and continued nausea and vomiting are concerns for those with obtundation, nausea, severe dysphagia, or aspiration risk.

.

Consider normal saline bolus 250–500 cc if blood pressure is low.

.

If the blood pressure is high, antihypertensive treatment is discussed in subsequent chapters (Chapters 3, 4, 5, and 8).

n What was the time of onset? .

Determining the exact time of onset is critical for establishing eligibility for acute therapies, especially TPA (Chapter 4). It is very important to be a detective. You will usually be told a time by the paramedics or ED triage nurse, but be sure to recheck the information you receive from them. If possible, try to speak personally with first-hand witnesses, nursing home staff, etc. Often paramedic information is based on an inexact estimate given to the paramedic when they arrive on scene, and then gets handed down as fact. You can often help establish the time of onset by finding out the time that the emergency call arrived at the dispatch center, and work backwards with the person who called. Other useful questions are to remind bystanders of their daily routine, TV shows, etc. that might help them accurately establish the time they found the patient or called the emergency services.

.

In most cases, the onset is not observed – the patient is found with the deficit. In that case, or in patients who awaken

9


What to do first

10


with symptoms, the onset time is the time the patient was last seen normal. However, if the patient awoke with symptoms, be sure to ask if the patient was up in the middle of the night for any reason (often to go to the bathroom) – as sometimes this puts the patient in the time window for treatment.

n How bad are the symptoms now? .

Examine the patient and do the NIH stroke scale (NIHSS) (Appendix 14).

.

The initial stroke severity is the most important predictor of outcome.

n Do a non-contrast head CT .

This will immediately rule out hemorrhage (Chapters 8, 9) as blood is bright on a CT. The initial head CT should not show obvious acute ischemic changes in patients with ischemic infarcts who are eligible for acute interventions (Chapters 3–7), as acute ischemic changes become increasingly apparent between 3 and 24 hours.

.

The result will determine the first major branching point in therapeutic decision-making, to be covered in the subsequent chapters.

.

Obtaining the CT is often the major impediment in preparing for thrombolytic therapy, so efforts should be made to shorten ‘‘door to CT’’ time, which should be below 30 minutes. For instance, we allow the triage nurse to order the CT scan if a stroke is suspected, and stroke patients will get preference over any other patient for CT access. Another problem is prompt reading of CT scans, especially in small hospitals in

Recommended diagnostic evaluation

rural communities. Make sure to notify the reading radiologist that this patient is a possible TPA candidate. .

In some select centers, emergent MRI can be done very quickly and substitute for CT, but this is the exception. In general, MRI is deferred until after the first decision is made whether to treat with TPA.

n If the CT shows no blood, try to get the artery open .

TPA is the only FDA-approved treatment for ischemic stroke, and you should immediately begin to determine if the patient is eligible for this therapy, and prepare for its administration. The TPA protocol is detailed in Chapter 4.

n Recommended diagnostic evaluation .

The American Stroke Association guidelines list the following diagnostic studies for immediate use in a patient with suspected acute ischemic stroke.1,2 These should be ordered in the ED, but you should not delay TPA treatment waiting for results once the patient meets established criteria (Chapter 4).

All patients &

brain CT (brain MRI could be considered at qualified centers)

&

electrocardiogram

&

blood glucose

&

serum electrolytes

&

renal function tests

11


What to do first

12


&

complete blood count, including platelet count

&

prothrombin time/international normalized ratio

&

activated partial thromboplastin time

Selected patients &

hepatic function tests

&

toxicology screen

&

blood alcohol determination

&

pregnancy test

&

oxygen saturation or arterial blood gas tests (if hypoxia is suspected)

&

chest radiography (if lung disease or aortic dissection are suspected)

&

lumbar puncture (if subarachnoid hemorrhage is suspected and CT is negative for blood)

&

electroencephalogram (if seizures are suspected)

3 Ischemic stroke

This chapter discusses the four main components of acute ischemic stroke care. The sections on prevention of complications and recovery and rehabilitation are applicable to both ischemic and hemorrhagic stroke patients.

n Definition An ischemic stroke is death of brain tissue due to interruption of blood flow to a region of the brain, caused by occlusion of a cerebral or cervical artery or, less likely, a cerebral vein.

n Etiology The etiology of the ischemic stroke is important to help determine the best treatment to prevent another stroke. However, regardless of etiology, initial therapy is for the most part the same, and so initially, the most important thing is to implement the acute measures described in this chapter.

n Diagnosis The first important task is to differentiate between ischemic and hemorrhagic stroke, which can be done with a head CT. Detailed brain and vascular imaging are critically

13

Ischemic stroke

14


important but should not delay assessment for TPA candidacy. There are things that can mimic stroke (see Chapter 1). A focused history should quickly exclude stroke mimics. Unless the presentation is atypical or a stroke mimic is suggested, one should assume it is a stroke and proceed with the determination of whether or not the patient is a candidate for acute therapy. A detailed diagnostic evaluation should be deferred.

n The four components of ischemic stroke care There are four components to caring for people with acute ischemic stroke. At every point, you should be thinking about the four issues: (1) Acute therapy and optimization of neurological status. (2) Etiological work-up for secondary prevention. (3) Prevention of neurological deterioration or medical complications. (4) Recovery and rehabilitation. This chapter discusses the four components in brief, and then there are longer discussions on the following topics: .

TPA therapy (Chapter 4).

.

Neurological deterioration (Chapter 5).

.

Stroke prevention (Chapter 6).

.

Rehabilitation (Chapter 11).

See also the sample admission orders in Appendix 3.

n Acute therapy and optimization of neurological status The main goal of therapy is to get the artery open and re-establish blood flow. You should always ask yourself if you


are doing everything possible to optimize blood flow to regions of cerebral ischemia.

INTRAVENOUS RECOMBINANT TISSUE PLASMINOGEN ACTIVATOR (TPA) In this book, we will refer to recombinant tissue plasminogen activator as TPA, because that is what it is usually called in the busy emergency department. However, the reader should be aware that this drug is also referred to as rt-PA, t-PA, tPA, alteplase (generic name) or Activase (trade name). .

Intravenous TPA is the only FDA-approved treatment for ischemic stroke in the USA. It is approved under safety monitoring in the European Union. Intra-arterial (IA) thrombolysis is a rescue therapy that is being used in several centers under various research protocols. A variety of neuroprotective agents (hypothermia, other drugs) are presently under investigation to try to decrease infarct size, but none is FDA-approved at this time.

.

The current guideline is that TPA should be given if the patient meets criteria for treatment.2 Details of the protocol can be found in Chapter 4.

CONCURRENT DIAGNOSTIC TESTING Determination of stroke etiology is usually deferred until after starting TPA therapy. However, while considering or instituting TPA, concomitant information about vascular and tissue status may be helpful. For instance, detection of large-artery occlusion or stenosis is particularly helpful in planning acute recanalization strategies and risk stratification for recurrent stroke or neurological deterioration.

15


Ischemic stroke

16


The following diagnostic tests may be helpful in determining the stroke mechanism, however, the need to do acute studies depends on a balance of availability of therapy, time requirement, clinical suspicion, and cost. .

Head CT should already have been done, as it is one of the vital first steps in the management of the stroke patient and helps to exclude hemorrhage (see Chapter 2).

.

Transcranial Doppler ultrasound (TCD) can be performed to detect occlusion, recanalization, and reocclusion of the large intracranial arteries in real time and can be brought to the patient’s bedside in the emergency department.

.

CT angiography (CTA) can quickly provide a snapshot of the entire cerebral arterial anatomy, and can diagnose intracranial and extracranial stenoses, aneurysms, or dissections. It is important to know the patient’s creatinine prior to the administration of IV contrast and exclude a contrast allergy.

.

MR angiography (MRA) of the neck and circle of Willis provides the same information as CTA without risk of contrast. However, patients must be cooperative to hold still for several minutes, and those with a pacemaker and some with aneurysm clips or stents may not be eligible for MRI scanning.

.

MR imaging (MRI) of the brain can provide substantial information on stroke localization, age, bleeding, and tissue status (see Appendix 5). However, the same caveats apply as with MRA.

MAINTENANCE OF CEREBRAL PERFUSION To maximize brain perfusion through stenoses and collateral vessels, we maintain euvolemia, support blood pressure, and put the head of the bed flat.


Do not treat hypertension acutely* unless: (1) the patient was treated with TPA* or (2) the patient has acute hypertensive end organ damage (congestive heart failure, myocardial infarction, hypertensive encephalopathy, dissecting aortic aneurysm, etc.)* or (3) systolic or diastolic pressures are above 220 or 120 mm Hg respectively* If you are going to treat hypertension, consider using a shortacting agent that will wear off quickly or be turned off in case BP drops too much, such as: .

labetalol (Trandate, Normodyne) 10–20 mg IV*

.

nicardipine (Cardene) 5 mg/hr IV infusion as initial dose; titrate to desired effect by increasing 2.5 mg/hr every 5 minutes to maximum of 15 mg/hr*

Goal: Blood pressure reduction by 10–15%. See Table 3.1 for current guidelines on the treatment of hypertension in acute ischemic stroke. In the absence of controlled prospective data, there is some consensus but still significant uncertainty about what levels of blood pressure to treat, how fast to lower the pressure, and what drugs to use. In acute ischemic stroke, we follow the guidelines in Table 3.1; we use nicardipine most commonly in the ED and during the first 24 hours to titrate blood pressure smoothly to desired levels.

Other options for maintenance of cerebral perfusion .

Normal saline for IV fluids – to maintain euvolemia and because it is isotonic and will not cause fluid shifts: &

.

consider normal saline 500 cc bolus over 20–30 minutes.

Consider hetastarch (Hespan, Hextend) for volume expansion: &

hetastarch 500 cc over 1 hour;

17


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Ischemic stroke

Table 3.1. Approach to elevated blood pressure in acute ischemic stroke. Blood Pressure Level (mm Hg)

Treatment

A. Not eligible for thrombolytic therapy Systolic < 220 Observe unless other end-organ involvement, OR e.g., aortic dissection, acute myocardial Diastolic < 120 infarction, pulmonary edema, hypertensive encephalopathy Treat other symptoms of stroke such as headache, pain, agitation, nausea, and vomiting Treat other acute complication of stroke, including hypoxia, increased intracranial pressure, seizures, or hypoglycemia Systolic > 220 Labetalol 10–20 mg IV over 1–2 min OR May repeat or double every 10 min Diastolic (maximum dose 300 mg) < 121–140 or Nicardipine 5 mg/hr IV infusion as initial dose; titrate to desired effect by increasing 2.5 mg/hr every 5 min to maximum of 15 mg/hr Aim for a 10% to 15% reduction of blood pressure Diastolic > 140 Nitroprusside 0.5 mg/kg/min IV infusion as initial dose with continuous blood pressure monitoring Aim for a 10% to 15% reduction of blood pressure B. Eligible for thrombolytic therapy Pretreatment Systolic > 185 Labetalol 10–20 mg IV over 1–2 min OR May repeat 1 OR Nitropaste 1–2 inches Diastolic > 110 If blood pressure is not reduced and maintained at desired levels (systolic 185 and diastolic 110), do not administer TPA


Table 3.1. (cont.) Blood Pressure Level (mm Hg)

Treatment

During and after treatment 1. Monitor BP Check BP every 15 min for 2 hours, then every 30 min for 6 hours, and then every hour for 16 hours 2. Diastolic > 140 Sodium nitroprusside 0.5 mg/kg/min IV infusion as initial dose and titrate to desired blood pressure 3. Systolic > 230 Labetalol 10 mg IV over 1–2 min OR May repeat or double labetalol every 10 min Diastolic to a maximum dose of 300 mg or give the 121–140 initial labetalol bolus and then start a labetalol drip at 2 to 8 mg/min or Nicardipine 5 mg/hr IV infusion as initial dose; Titrate to desired effect by increasing 2.5 mg/hr every 5 min to maximum of 15 mg/hr. If BP is not controlled by labetalol, consider sodium nitroprusside 4. Systolic Labetalol 10 mg IV over 1–2 min 180–230 May repeat or double labetalol every 10 to OR 20 min to a maximum dose of 300 mg or Diastolic give the initial labetalol bolus and then start 105–120 a labetalol drip at 2 to 8 mg/min Source: H. P. Adams Jr., R. J. Adams, T. Brott, et al., Guidelines for the early management of patients with ischemic stroke: a scientific statement from the Stroke Council of the American Stroke Association. Stroke 2003; 34: 1056–83.1 Reproduced with permission from Lippincott Williams & Wilkins.

19


Ischemic stroke

20


&

then consider hetastarch 250 cc IV every 8 hours. Monitor jugular venous pressure and input/output. Watch for fluid overload.

.

Consider phenylephrine (Neo-Synephrine) drip, or other pressors, in ICU for induced hypertension.

ANTIPLATELET AND ANTICOAGULANT THERAPY AS AN ACUTE TREATMENT FOR ISCHEMIC STROKE Both antiplatelet and anticoagulant therapy are often considered in the acute therapy of ischemic stroke, and one or both may be appropriate, but randomized trials have shown that anticoagulants should not be routinely employed acutely. Trials have shown that antiplatelets have only a modest benefit, and no studies have yet shown the benefit of urgent antiplatelet treatment.

Acute antiplatelet therapy Aspirin for acute stroke has been shown to be effective, though only marginally, when studied in thousands of patients.3,4* Antiplatelet treatment beyond aspirin is driven by evidence from acute cardiovascular trials until there are more stroke data available, remembering of course the greater propensity of the brain to develop hemorrhagic complications. We give aspirin 81–325 mg to most patients. In patients who have had strokes or TIAs while already on antiplatelet therapy, who have a fluctuating neurological course, or who have a heavy burden of atherosclerotic risk factors or atherosclerotic lesions, we will often orally load the patient in the emergency department with clopidogrel (Plavix) 375 mg, and then aspirin 81 mg and clopidogrel 75 mg once daily for the first few days. The idea of an oral load stems from studies in patients


undergoing coronary procedures who have less periprocedural ischemic complications if they receive a load pre-procedure. We then switch to aspirin/dipyridamole combination (Aggrenox, Asasantin)* or aspirin alone* or clopidogrel alone* if the patient is going home on antiplatelets.

Acute anticoagulant therapy Anticoagulation for acute ischemic stroke has never been shown to be effective.3* Even among those with atrial fibrillation, the stroke recurrence rate is only 5–8% in the first 14 days, which is not reduced by early acute anticoagulation.5,6* Anticoagulation is mostly used for long-term secondary prevention in patients with atrial fibrillation and cardioembolic stroke at this point. Without convincing supporting data, some clinicians advocate acute anticoagulation with heparin in certain cases. These include patients with a cardioembolic condition at high risk for recurrence (thrombus on valves, or mural thrombus), documented large-artery (ICA, MCA, or basilar artery ) occlusive clot at risk for distal embolism, arterial dissection, or venous thrombosis. Such patients may be started on heparin acutely and transitioned to warfarin (Coumadin). If ordering heparin, use weight-adjusted algorithm with no bolus*. Enoxaparin (Lovenox) at 1 mg/kg subcutaneously every 12 hours may be used in place of heparin. How long should you wait before starting anticoagulation? There are no clear data on this topic. There is concern that the risk of hemorrhagic conversion is increased with anticoagulation, particularly in patients with large strokes. Hemorrhagic transformation is frequent in the evolution of large infarcts, especially those that have been reperfused either by spontaneous recanalization or with thrombolytics. One should be

21


22


Ischemic stroke

particularly careful about early anticoagulation in these patients. One generally waits 2–14 days before starting anticoagulation, the specific duration depending on the urgency of the indication versus the risks. You must carefully weigh the risks and benefits on a case by case basis, and never start anticoagulants without obtaining brain imaging first, to exclude ongoing hemorrhagic evolution or brain swelling.

HYPERGLYCEMIA Hyperglycemia is known to worsen stroke outcome. The mechanism by which and level at which hyperglycemia worsens stroke is not known. However, there are data that show even modest hyperglycemia (glucose > 150 mg/dl) enlarges eventual stroke size and increases the risk of brain hemorrhage. Therefore, treat glucose aggressively. See Appendix 8 for insulin algorithm.

HYPERTHERMIA Hyperthermia has been correlated with poor outcome. Experimentally, increasing the body temperature of animals increases metabolic demand and infarct size. Therefore, treat hyperthermia aggressively with acetaminophen (Tylenol) and cooling blankets if necessary.*

n Etiological work-up for secondary prevention See also Chapter 6, which covers in more detail the evaluation of stroke patients and how to choose secondary prevention strategies in relation to the results of the diagnostic considerations.


With brain imaging and vascular evaluation we try to find a specific etiology such as cardioembolic source, arterial stenosis, etc. (Fig. 3.1). At the same time, we look for reversible risk factors for recurrent stroke such as hypertension, diabetes, hypercholesterolemia, and smoking/substance abuse that will need to be addressed. There are several different ways to classify strokes (based on severity, location, size, etc.), but for planning a secondary stroke prevention strategy we find the following TOAST classification8 most useful, since it is based on stroke mechanism. .

Large-artery atherosclerosis: intracranial, extracranial (carotid, aortic arch).

.

Cardioembolic: atrial fibrillation, segmental wall akinesis, paradoxical embolus, etc.

.

Small vessel: lacunar infarction.

.

Other: unusual causes (dissection, venous thrombosis, drugs, etc.).

.

Unknown: cryptogenic.

SCREENING FOR ARTERIAL STENOSIS/OBSTRUCTION MR angiography (MRA) shows arterial stenosis intracranially and extracranially, and excludes large aneurysms and vascular malformations. It is a good screening tool. Recent data indicate that contrast-enhanced MRA might be the most reliable of non-invasive tests.9 In our hands, carotid ultrasound is better at estimating the degree of internal carotid artery (ICA) stenosis at the bifurcation. TCD complements other vascular imaging and can also be used to follow changes over time. You will often focus on the origins of the internal carotid arteries, but do not forget the vertebral artery origins and

23


24


Ischemic stroke

Intracranial Atherosclerosis

Carotid Plaque with Arteriogenic Emboli

Aortic Arch Plaque

Penetrating Artery Disease

Flow Reducing Carotid Stenosis

Atrial Fibrillation Valve Disease

Cardiogenic Emboli

Left Ventricular Thrombi

Figure 3.1. Mechanisms of stroke. Source: G. W. Albers, P. Amarenco, J. D. Easton, R. L. Sacco, & P. Teal, Antithrombotic and thrombolytic therapy for ischemic stroke: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest 2004; 126 (3 suppl.): 483S–512S.7 Reproduced with permission.


intracranial arteries that often harbor atherosclerotic narrowing which may be the etiology of the stroke. Digital subtraction angiography (DSA) is considered the gold standard for visualizing the arteries, but is not without risk. CT angiography can give you sufficient detail and can be done quickly from the ED. DSA often takes much longer to obtain due to the need to organize the angiography team. For determining degree of arterial stenoses, seeing arterial dissection, or other vascular abnormalities, however, DSA is still considered the gold standard.

CARDIAC EVALUATION An electrocardiogram (EKG) should be done to exclude atrial fibrillation and to rule out silent myocardial infarction or ischemia, which may occur as a consequence of the stroke. If atrial fibrillation or other important arrhythmia is suspected, cardiac telemetry or Holter monitor is needed. An echocardiogram is helpful in looking for a cardioembolic source and right-to-left shunts. A transthoracic echocardiogram (TTE) can show wall motion abnormalities (anterior wall akinesis carries high embolic risk), low left ventricular ejection fraction (315 mosm. .

Cerebrospinal fluid drainage by ventriculostomy may help if hydrocephalus is contributing to increase ICP.

SURGICAL THERAPY .

Obtain neurosurgical consultation early.

.

For large MCA infarcts, consider early decompressive hemicraniectomy. The skull is taken off (and put in freezer) and dural incision is made so that the brain can swell out rather than compress the brainstem (see below).

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Neurological deterioration in acute ischemic stroke

54


.

For cerebellar stroke, the appropriate treatment is posterior fossa decompression and cerebellectomy.

.

With both procedures, a common error is not to remove enough bone, resulting in inadequate decompression. Be sure the neurosurgeon knows the anatomical guidelines for decompression. They are included below as a guide and Fig. 5.2 shows an outline of the surgical method.

Decompressive surgery is a life-saving measure. While it has never been proven effective in a randomized study, most stroke experts recommend it in highly selected cases based on case series. It is particularly recommended for large cerebellar strokes, as people can be quite functional without a large part of their cerebellum. However, with respect to large MCA strokes, talk with family about quality of life after stroke survival versus death. Many do not perform the procedure as often for large left MCA strokes as the patient is likely to be left aphasic. Age is an important predictor of outcome after hemicraniectomy, all other things being equal, with less likelihood of acceptable outcome in patients over 60 years old. Best results occur with early intervention in young patients with nondominant-hemisphere strokes.

Criteria for consideration of hemicraniectomy .

50% MCA territory hypodense

.

7.5 mm midline shift

.

>4 mm midline shift with lethargy

Other criteria include: &

age < 60

&

145 cc infarct volume on MRI

Cerebral edema and mass effect

Figure 5.2. Method for hemicraniectomy.

Guidelines for adequate surgical decompression from ongoing clinical trials .

anterior: frontal to mid-pupillary line

.

posterior: 4 cm posterior to external auditory canal

55



56


.

superior: superior sagittal sinus

.

inferior: floor of middle cranial fossa

.

durotomy over the entire region of decompression

.

dural grafting

Other criteria include: &

12 cm diameter craniectomy

n Hemorrhagic transformation This should be clearly visible on non-contrast head CT (Fig. 5.3). Most of the time, the patient is asymptomatic from the hemorrhagic transformation (also known as hemorrhagic conversion), unless it is large or in a critical location. Radiographically, hemorrhagic transformation is divided into four categories.24 .

Hemorrhagic infarct 1 and 2 (HI1 and HI2) represent petechial bleeding into the area of infarct without mass effect and are rarely symptomatic. HI1 are small petechiae. HI2 are confluent.

If HI occurs, usually there is not much you can do or should do, except to stop antiplatelets and anticoagulants temporarily until you are sure there is no continued bleeding on repeat brain imaging. .

Parenchymal hemorrhage 1 and 2 (PH1 and PH2) represent confluent bleeding. If the bleeding takes up more than 30% of the infarcted area and produces mass effect (PH2), it usually produces neurological deterioration.

The risk of developing PH2 is the main reason why anticoagulation is not recommended immediately after cardioembolic stroke, and without repeat brain imaging first. These should be managed similarly to any other cerebral hemorrhage (Chapter 8).

Hemorrhagic transformation

Figure 5.3. Types of hemorrhagic transformation: HI1 (top left), HI2 (top right), PH1 (bottom left), and PH2 (bottom right).24 Source: M. Fiorelli, S. Bastianello, R. von Kummer, et al., Hemorrhagic transformation within 36 hours of a cerebral infarct: relationships with early clinical deterioration and 3-month outcome in the European Cooperative Acute Stroke Study I (ECASS I) cohort. Stroke 1999; 30: 2280–4.24 Reproduced with permission from Lippincott Williams & Wilkins.

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n Metabolic disturbance These are pretty self-explanatory. Remember that a sick brain is more sensitive to the effects of metabolic perturbations, so these should be sought and aggressively treated. .

Mild fever or changes in sodium or glucose may have an exaggerated clinical effect.

.

Any intercurrent infection such as urinary tract infection or pneumonia will magnify the neurologic findings.

.

Reduced cardiac output is a particularly bad comorbidity resulting in worse clinical outcome, and should be carefully avoided by optimizing fluid and inotropic therapy.

.

Remember also that ‘‘if the lips are blue, the brain is too,’’ so look for, determine the cause of, and treat arterial oxygen desaturation. Possible causes: &

pulmonary embolism

&

pneumonia

&

pulmonary edema

.

Anemia: transfuse for hemoglobin < 10 g.

.

Sedative drugs interfere with rapid transition to rehabilitation mode and have also been associated with worse outcome, decreased mobilization with attendant increased DVT, etc. Sedating drugs should be avoided as far as possible. See The uncooperative patient, below.

n Seizure Seizures occur in roughly 20% of all strokes, and are somewhat more frequent after hemorrhage than infarct. Most of the time, if seizures occur, they will appear at the time of stroke onset or within 24 hours. Seizures will often cause a post-ictal depressed level of consciousness, as well as worsening of the focal signs.

Symptom fluctuations without a good cause

.

Most authorities recommend withholding anticonvulsants unless the seizures are recurrent.

.

Status epilepticus after acute stroke is exceedingly rare.

.

For recurrent seizures or status, start with fosphenytoin 20 mg/kg IV, then after 12 hours maintenance phenytoin 200–300 mg per day.

.

Intubation may be necessary to protect the airway in patients who already are impaired from their stroke.

.

Aspiration pneumonia is common after seizures and should be assumed to occur if the seizure is generalized or intubation is necessary.

.

If delayed or recurrent seizures occur, then non-sedating anticonvulsants such as the following are recommended, in this order: &

lamotrigine: 25 mg per day titrating up every 2 weeks by 50 mg to 150 mg per day

&

gabapentin: 300 mg per day titrating up every 3–4 days to 1500 mg per day in divided doses

&

levetiracetam: 500 mg every 12 hours titrating up every 2 weeks to 2000 mg per day

n Symptom fluctuations without a good cause Some patients deteriorate without an obvious explanation. This is a poorly understood phenomenon. It is commonly seen with subcortical strokes. While this usually occurs in the first three days, it can occur up to two weeks after stroke onset. The mechanism is unknown. Local hypoperfusion? Inflammation? Neurochemical or neurotransmitter changes? Apoptosis?

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Treatment is mainly supportive (maintain euvolemia, check blood pressure to make sure it doesn’t drop, put head of bed flat). Anti-inflammatory (i.e., high-dose statins) and other neuroprotective therapies are under evaluation. One recent study of a free radical trapping drug showed improved outcome in acute ischemic stroke patients, indirectly supporting the laboratory evidence demonstrating an important role of inflammation in producing damage after stroke.25

n The uncooperative patient Patients can become confused after a stroke. Contributing factors include advanced age and underlying dementia, placement in a disorienting critical-care environment, and sleep deprivation. Often, movement to a quiet private room helps, but this has to be balanced against less close scrutiny and treatment of medical complications outside the stroke unit or ICU setting. While sedation should be avoided, low doses of antipsychotic agents can be useful and are used commonly – such as haloperidol PO or IV 0.5–2.0 mg, risperidone 1 mg PO and quetiapine 25 mg PO. There are also data to suggest that newer antipsychotic agents increase mortality of patients with dementia, though this was with prolonged treatment (10–12 weeks).26 Therefore pharmacologic management of agitation and confusion should be practiced with caution. Good nursing care, orientation, and calm environment are important.

6 Ischemic stroke prevention: why we do the things we do In this chapter, we discuss mainly secondary prevention for stroke, although many of the measures, especially control of risk factors and lifestyle changes such as not smoking, controlling blood pressure, etc., are also important measures to avoid a first stroke. Initially, we discuss a tailored diagnostic work-up, then general measures for secondary prevention of ischemic stroke, and finally recommendations for specific conditions that are associated with a high risk of stroke.

n Investigations The goal of the ‘‘stroke work-up’’ is to find the cause of the stroke in order to determine the best treatment options to maximize the chance of preventing another stroke. A thorough ischemic stroke work-up is not just CT/MRI/ MRA/ECHO/CAROTIDS/TCD/LIPIDS/HBA1C. There is no ‘‘cookbook’’ work-up for ischemic stroke. It is important to consider the patient’s risk factors and stroke syndrome when determining the extent of the diagnostic evaluation. For instance, a 75-year-old man with longstanding hypertension, diabetes, and hypercholesterolemia and a

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Ischemic stroke prevention: why we do the things we do

62


lacunar infarct confirmed on brain imaging may need little additional work-up beyond a carotid ultrasound and EKG. However, a 40-year-old man with no known risk factors and an acute stroke would require an extensive evaluation. The following is a list of the studies that we consider in most stroke patients to distinguish stroke subtype and tailor our preventive measures. In Appendix 12 we will address the additional evaluation for young stroke patients with no risk factors, and others where the underlying cause may be more obscure. In addition to the following, almost all stroke patients should have a complete blood count, electrolytes, creatinine, blood glucose, INR, PTT, and electrocardiogram (see standard orders in Appendix 3).

Initial acute head CT* .

To rule out ICH and other causes, to assess for old strokes, to detect early signs of ischemia.

MRI of the brain/MRA of the neck and brain (circle of Willis) .

To localize the lesion.

.

To try to understand the mechanism by integrating all MRI and MRA data:

.

&

small-vessel lacunar infarction

&

large-artery atherosclerosis

&

embolism

&

hemodynamic

&

venous

To say what’s acute and what’s old using diffusion-weighted sequence.

.

To understand the tissue physiology (perfusion imaging).

Investigations

.

To examine the entire cervical and cerebral vasculature for stenosis (atherosclerosis, dissection, etc.), aneurysm, arteriovenous malformation (AVM).

.

You can see many unexpected things, including incidental findings.

Possibly, repeat head CT .

To localize the lesion, if patient is unable to have an MRI.

.

To evaluate the deteriorating patient: &

to assess mass effect/edema

&

to look for hemorrhagic conversion

&

to look for stroke recurrence

CT angiogram (CTA) of the neck and brain (circle of Willis) .

To look for arterial stenosis, dissection, aneurysm (especially if the patient is unable to have an MRI).

Transthoracic echocardiogram (TTE) (order with ‘‘bubble study’’) .

To assess for embolic source (anterior wall or apical akinesis, clot, valvular disease, large PFO).

.

Low ejection fraction (20–30% is generally agreed upon as a cutoff) significantly increases thromboembolic risk due to stasis, and also should trigger further specific cardiac evaluation and treatment.

Transesophageal echocardiogram (TEE) (order with ‘‘bubble study’’) .

To assess for embolic source not seen well on TTE (aortic atheroma, PFO, atrial septal aneurysm, spontaneous echo contrast, left atrial appendage clot).

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64


.

If a PFO is found, we often will also do a screen for hypercoagulable states, a bilateral lower extremity ultrasound, and MR venogram of the pelvis to look for venous thrombosis. See discussion on PFO at the end of this chapter.

Carotid ultrasound (CUS) .

To assess for internal carotid artery stenosis or occlusion.

.

Shows you direction of vertebral artery flow.

.

You might not need it if you have a good-quality normal MRA or CTA of the extracranial circulation. CUS can be used to confirm a stenosis seen on MRA or CTA. If these non-invasive tests are concordant, it may not be necessary to do an invasive DSA to determine candidacy for endovascular or surgical treatment of a carotid stenosis.

Transcranial Doppler (with or without bubble study) .

To monitor clot presence and lysis in the acute setting.

.

To confirm intracranial stenosis/occlusion of major arteries seen on MRA or CTA.

.

Emboli detection/monitoring.

.

Look for PFO by injecting microbubbles. TCD with ‘‘bubble study’’ is the most sensitive and least expensive/invasive way to screen for right to left shunting.

.

Hemodynamic reserve (breath holding index, vasomotor reactivity).

.

Evaluate collateral flow patterns.

Digital subtraction angiography (DSA) .

Gold standard for determining degree of stenosis.

.

Only way to definitively delineate and follow aneurysms or AVMs, dissection, vasculitis, or other arteriopathies.


Fasting lipids .

Look for high total cholesterol, triglycerides, LDL (target LDL < 100 mg/dL; for very high-risk patients LDL < 70 mg/dL).

.

Look for low HDL.

Hemoglobin A1c (HbA1c) .

Screen for diabetes and its recent control.

n Ischemic stroke prevention: general measures Educate your patients so they can take an active role in their health care and secondary prevention of ischemic stroke. Try to convert patients to the medications that they will be going home on prior to discharge, to make sure they tolerate them. Also, take cost issues into account. A patient who cannot afford the medications will not take them. The following are derived from the most recently published guidelines, which should be consulted for details.27

(1) CONTROL RISK FACTORS .

Hypertension(based on SHEP trial, and others).28* See below for more detail.

.

&

ACE inhibitors (HOPE, PROGRESS trials).29,30*

&

Diuretics and calcium channel blockers (ALLHAT trial).31*

Elevated lipids: &

Statins (several trials, including MRC Heart Protection Study).32

&

Target LDL 70 mg/dl according to the most recent guidelines for high-risk cardiovascular patients.33

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66


&

Be sure to get baseline liver functions before starting statin therapy.

.

Smoking: &

.

.

Cessation counseling and pharmacotherapy.

Diabetes: &

Identification.

&

Treatment, including diet.

Hyperhomocysteinemia: &

May justify folic acid, B12, B6 treatment, but so far there is no evidence that vitamins – including folic acid – are effective for stroke prevention in general (VISP study).34

&

Therefore, since there is no effective treatment for this risk factor for stroke, routine screening for hyperhomocysteinemia is probably not cost-effective.

.

Estrogen use (WEST trial, Women’s Health Initiative):35–37* &

.

Avoid in most cases.

Drugs of abuse and alcohol: &

Should be avoided and discouraged, especially vasoactive drugs such as cocaine and amphetamines.

&

No more than two drinks per day.

(2) ANTITHROMBOTIC OR ANTICOAGULANT MEDICATIONS .

Aspirin (many studies).38* 20% relative risk reduction of secondary stroke/other vascular events. Doses of 50 mg daily or higher; usually give 81 or 325 mg.

.

Aspirin/dipyridamole ER (Aggrenox, Asasantin). ESPS-1 and ESPS-2 trials; 30% better than aspirin alone.39,40* &

The PRoFESS trial (ongoing) is comparing aspirin/dipyridamole ER (Aggrenox) to clopidogrel (Plavix).


.

Clopidogrel (Plavix). CAPRIE trial.41* Slightly better than aspirin, particularly in patients with peripheral vascular disease, and better tolerated.

.

Aspirin/clopidogrel combination. Long-term use increases bleeding rate without benefit of greater stroke prevention (MATCH and CHARISMA studies).42,43 Therefore the combination is not recommended long-term (more than a few days) unless the patient has had a recent stent placed.

.

Warfarin (Coumadin). For most of the following, the use of warfarin can be considered based on either randomized trials (level A) or consensus recommendations (level C). However, except for those with Class 1 evidence (i.e., where there is general agreement with its use), either antiplatelet drugs or warfarin can be used. &

Atrial fibrillation except for ‘‘lone AF’’ (see below) (SPAF trials).44,45* Class 1, level A evidence.

&

Critical extracranial carotid stenosis. String sign or occlusion (anecdotal experience).

&

Basilar thrombosis/stenosis (anecdotal experience).

&

Arterial dissection (consensus statements).

&

Other ‘‘embologenic’’ cardiac conditions:46 .

rheumatic valvular disease or mechanical valve (class 1 evidence)

.

low left ventricular ejection fraction ( 4 mm (from SPAF III subgroup analysis, consensus recommendation)47,48

&

Embolic-looking cryptogenic stroke (randomized trial – WARSS subgroup analysis)49,50

&

Stroke patients with documented coagulopathy (consensus statements) .

Especially if history or evidence of venous thrombosis, or pulmonary embolism

.

Also patients with full antiphospholipid antibody syndrome (venous thrombosis, miscarriages, livedo reticularis)

&

Venous infarction due to cerebral venous sinus thrombosis (consensus statements)

.

Based on the following randomized trials, warfarin is not routinely indicated for: &

stroke due to intracranial atherosclerosis (WASID study),51

&

most non-cardioembolic strokes (WARSS),52

&

most stroke patients with positive antiphospholipid antibody (APASS: a WARSS substudy),53 or

&

most patients with PFO (PICCS: a WARSS substudy).50*

(3) LIFESTYLE MODIFICATION Lifestyle modification may reduce the risk factors mentioned above. .

Stop smoking. This is one of the most important things patients can do, to prevent not only ischemic stroke but also heart disease, lung cancer, and head and neck cancer, etc.

.

Better diet. Refer patients to a dietician who can talk with patients about a low-fat diet and diabetic diet if applicable.

.

More exercise. Counsel the patient to adopt a less sedentary lifestyle and participate in even moderate exercise.


(4) BLOOD PRESSURE CONTROL* Hypertension is the single most important modifiable risk factor. JNC 7 reports that the risk of cardiovascular disease, beginning at 115/75 mm Hg, doubles with each increment of 20/10 mm Hg.54 .

Multiple large randomized controlled trials have shown efficacy of antihypertensive treatment in primary and secondary prevention of stroke. The selection of antihypertensives remains unsettled and controversial.

.

Many drugs have been shown to reduce stroke in primary prevention (beta-blocker in SHEP, diuretic in SHEP and ALLHAT, calcium channel blocker in ALLHAT, ACE inhibitor in HOPE and PROGRESS, ARB in LIFE).28–31,55

.

A combination of perindopril (Aceon), a tissue-specific ACE inhibitor, and indapamide (Lozol), a diuretic, have been shown to reduce stroke in secondary prevention even among non-hypertensive patients (PROGRESS).30 Whether this effect is due to the tissue-specific ACE inhibition rather than an ACEinhibitor class effect, or whether an ACE inhibitor needs to be used in combination with a diuretic, remains controversial.

.

Probably the most important point is blood pressure reduction, not the specific drug. For primary prevention, a diuretic seems to be effective and cheap. Recent meta-analysis seems to support the superiority of diuretics.56 JNC 7 also recommends thiazide diuretics as a first-line pharmacologic therapy, though it recognizes that more than one drug is commonly needed.

.

In the hospital setting, especially after a stroke, a patient’s fluid intake may be poor. A diuretic while on IV fluids does not make sense. Start a diuretic in stroke inpatients only if the patient is drinking fluids consistently.

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JNC 6 Category

JNC 7 Category SBP/DBP

Optimal

140/90

Hypertension

Stage 1

140–159/90–99

Stage 1

Stage 2

160–179/100–109

Stage 3

>180/110

Normal Prehypertension

Stage 2

Sources: The sixth report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. Arch Intern Med 1997;157:2413–46. The seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. JAMA 2003;289:2560–2571.

Figure 6.1. Recent JNC 6 and 7 blood pressure categories.54

.

Bring down BP slowly with oral antihypertensives after acute ischemic stroke.

.

According to recent guidelines (Fig. 6.1), the target blood pressures are the following: &

10% stroke risk per year.

&

So, by definition, any atrial-fibrillation patient with embolic stroke or TIA is considered ‘‘high risk.’’

&

Age > 80: >7% per year.

&

Echocardiographic risk features include: left ventricular dysfunction, left atrial enlargement or clot, mitral annular calcification, spontaneous echo contrast.

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72


TREATMENT OF CHRONIC ATRIAL FIBRILLATION .

The choice of antiplatelet therapy vs. warfarin depends on the risk of stroke. Table 6.1 shows the risk reduction with treatment of A-fib patients according to their various risk categories.

Primary stroke prevention with warfarin (Coumadin)* .

Ischemic stroke risk decreased to 2% per year, or 60% relative risk reduction.

.

Major bleeding risk: 1.5%–2% per year. &

Increased risk with recent hemorrhage, falling, advanced age, alcohol binge, closed head injury, liver disease, aspirin, NSAIDs, cancer, age, previous stroke, uncontrolled hypertension.

.

.

ICH risk: 0.2–0.4% per year. &

Age 75: 0.5% per year (data from SPAFII).

&

Age > 75: 1.8% per year.

Target therapeutic INR is 2.0–3.0.

Primary stroke prevention with aspirin* .

Ischemic stroke risk decreased to 4% per year, or 20% relative risk reduction.

.

Major bleeding risk: 0.3–0.9 % per year.

.

ICH risk: 0–0.3% per year.

SECONDARY PREVENTION (MOST OF OUR CASES ON THE STROKE SERVICE) .

Warfarin reduces the risk of recurrent ischemic stroke from 10–12% per year to 4% per year.*

.

Target INR: 2.0–3.0.

Atrial fibrillation (A fib)

Table 6.1. Stroke risk reduction with aspirin and warfarin in different groups of patients with atrial fibrillation.

Risk strata Previous stroke or transient ischemic attack

Stroke rate with aspirin (%/y)

Relative risk reduction: warfarin vs. General aspirin (%) a NNTB b recommendation

10

60

17

Warfarin (INR 2–3)

55

35

2–4

45

75

200

Warfarin (INR 2–3) Warfarin or aspirin c Aspirin (81–235 mg/d)

Primary prevention High risk >4 Moderate risk Low risk

Notes: Step 1: Estimate the patient’s risk for stroke given aspirin. Several clinical schemes to stratify stroke risk in atrial fibrillation have been published; the Stroke Prevention in Atrial Fibrillation III scheme has been most widely validated. Step 2: Identify any special risks for hemorrhage during anticoagulation. Step 3: Based on estimated stroke risk and contraindications for anticoagulation, consider use of warfarin or aspirin. INR = international normalized ratio NNTB ¼ number needed to treat for benefit a The best overall estimate of relative risk reduction in stroke by warfarin over aspirin in unselected patients with atrial fibrillation is about 45%, but the magnitude varies with the inherent rate of stroke because of the varying ratios of warfarin-sensitive cardioembolic strokes to warfarin-insensitive noncardioembolic strokes.

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74


Notes to Table 6.1. (cont.) b

NNTB for 1 year with warfarin instead of aspirin to prevent one stroke, calculated on the basis of stroke rates of 10%, 5%, 3%, and 1% per year on aspirin for previous stroke, high-risk primary prevention, moderate risk, and low risk, respectively. c The choice of warfarin vs. aspirin should particularly consider patient values or preferences, individual bleeding risk, and availability of reliable anticoagulation monitoring. Adapted from: R. G. Hart, J. L. Halperin, L. A. Pearce, et al., Lessons from the Stroke Prevention in Atrial Fibrillation trials. Ann. Intern. Med. 2003; 138: 831–8.44 Reproduced with permission from the American College of Physicians.

n Carotid stenosis Carotid stenosis is also one of the better-studied causes of stroke for which specific therapy is available. There is a large body of literature on carotid endarterectomy and a large one is developing for carotid stenting. For review we recommend Barnett et al., 2002.57

SYMPTOMATIC INTERNAL CAROTID STENOSIS (70–99% BY NASCET CRITERIA OF ANGIOGRAPHIC STENOSIS) .

Surgery (carotid endarterectomy, CEA) is beneficial compared to medical therapy.58* &

2-year risk of ipsilateral stroke was 8.6% in the surgical group and 24.5% in the medical group (RRR 65%, ARR 16%, NNT 6 to prevent 1 stroke in 2 years).

&

It is most beneficial to those who have highest risk of subsequent stroke: those who had hemispheric symptoms (compared to ocular symptoms), tandem extracranial and

Carotid stenosis

intracranial disease, and those without apparent collaterals. &

Perioperative risk was 5.8% overall and was higher for those with contralateral internal carotid occlusion and those with intraluminal thrombus, but those high-risk patients still received benefit.

SYMPTOMATIC STENOSIS (50–69%) .

Benefit of surgery is marginal. &

5-year risk of any ipsilateral stroke was 15.7% surgical vs. 22.2% medical (ARR 7%, p ¼ 0.045).*

&

No benefit in preventing disabling strokes.

&

Women and those whose symptoms were limited to transient monocular blindness did not benefit.

&

6.7% 1-month surgical morbidity and mortality in NASCET.

ASYMPTOMATIC STENOSIS .

The risks vs. benefits of treating asymptomatic carotid stenosis must be weighed very carefully.

.

Two large randomized trials have shown that carotid endarterectomy for stenosis 60 70% reduces ipsilateral ischemic stroke compared to medical therapy*. &

ACAS showed that the 5-year risk was 5.1% for surgical vs. 11.0% for medical therapy.59

&

The results were confirmed by the ACST trial, which showed 5-year stroke risk of 6.4% for surgical vs. 11.8% for medical therapy.60

&

The overall subsequent risk is smaller than that for symptomatic carotid stenosis. The absolute risk reduction is

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76


about 1% per year, with NNT 17–19 to prevent 1 ipsilateral ischemic stroke in 5 years. &

The perioperative risk was 2.3% in ACAS and 3.1% in ACST.

&

If one considers surgical treatment for asymptomatic carotid stenosis, the surgeon must have volume and experience.

&

Women, for reasons which are unclear, have smaller benefit from carotid endarterectomy than men.

SURGERY: CAROTID STENTING VS. ENDARTERECTOMY .

Carotid stenting, though performed for several years now, is still considered investigational.

.

SAPPHIRE was a randomized trial designed to compare carotid stenting (with a distal protection device) to endarterectomy in high-risk patients with symptomatic and asymptomatic carotid stenosis. &

It showed that the stroke rates at two years are equivalent (stenting is not inferior) and there was a trend favoring stenting in rate of adverse events.61

.

Several ongoing studies, including CREST, SPACE, EVA-3 S, and CAVATAS-2, are examining the effectiveness of the procedure in stroke prevention. So far, safety appears similar to that of CEA except in patients > 80 years old.

.

Some unresolved issues are durability of the stent and restenosis rates. The eventual hope is that carotid stenting will be cheaper and safer, especially in those with multiple medical comorbidities.

.

Carotid stenting is approved for TIA and stroke patients where the stenosis is hard to reach surgically, where there are medical comorbidities that increase the risk of surgery, or in

Carotid stenosis

cases of post-radiation or postoperative stenoses. Outside of theses situations, stenting should be done only in the context of the aforementioned clinical trials.

WHEN CAN YOU DO SURGERY OR STENTING AFTER A STROKE? .

CEA performed early after a symptomatic event confers the greatest benefit since the highest risk of recurrent stroke is in the first two weeks after a TIA or minor stroke.

.

Combined data of NASCET and ECST trials show that the benefit of CEA is greatest with CEA performed within two weeks of symptoms.62,63 These trials, as well as a systematic review, saw no increased risk of early surgery (defined as earlier than 2–6 weeks).64 However, ‘‘unstable symptoms’’ or ‘‘urgent’’ surgery are also among the strongest risk factors for perioperative complications.

.

Traditionally, it has been recommended to wait 4–6 weeks after a large stroke to perform revascularization by CEA. The rationale is that reperfusing an area of recent stroke might lead to hyperperfusion or even hemorrhage. Breakdown of the blood–brain barrier and loss of autoregulation in the area of injury may lead to edema and bleeding. Also, at the time of stroke, it may be unclear how well the patient will recover and how aggressive to be with various prevention strategies.

.

In summary, it is probably best to revascularize early (within two weeks), especially after a TIA or if the stroke is small clinically and radiographically. There have been several studies in this regard, but none conclusive. A sense of ‘‘urgency’’ should be tempered with awareness of complications.

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n Acute carotid occlusion Carotid occlusion can cause a stroke by two mechanisms: hemodynamic reduction of flow or embolism into the downstream cerebral circulation. These two mechanisms can often be distinguished by the appearance of the stroke on MRI, and by perfusion studies. Hemodynamic strokes will have a ‘‘watershed’’ distribution of infarction and reduced flow in the distal beds of the MCA, ACA, and PCA, while emboli will have a classical embolic distribution of infarction and reduced flow in the branches of these vessels. .

Carotid occlusion patients are at high risk for recurrent stroke by either mechanism.

.

In general, patients with carotid occlusion are managed conservatively with risk factor reduction, careful maintenance of cerebral perfusion by cautious blood pressure control, and antiplatelet drugs. Aggressive intervention with anticoagulants or revascularization is mainly reserved for patients with small areas of infarction who are having continued symptoms and are at perceived risk of deterioration or recurrence.

.

One traditional approach is to anticoagulate acutely and for several months after acute symptomatic carotid occlusion to prevent distal emboli. The thinking has been that the end of the occlusion intracranially has an unstable clot that can propagate or embolize. However, there are no conclusive data supporting anticoagulation and substantial variability exists among stroke experts on this issue, so the decision is usually individualized from patient to patient.

.

Carotid occlusion can also be revascularized surgically (by CEA) or endovascularly (by intra-arterial lysis with or without stenting). The clot is usually at the internal carotid origin, and

Lacunar strokes

the rest of the artery downstream might be open. Though acute revascularization has been advocated by some, there are no prospective data to support the theory that acute revascularization (1) improves the patient’s symptoms from current stroke or (2) prevents recurrent stroke long-term. There are substantial risks to acute revascularization and such patients must be selected very carefully. .

In the USA there is an ongoing randomized NIH-sponsored trial in patients with chronic carotid occlusion evaluating extracranial–intracranial bypass surgery versus medical therapy (Carotid Occlusion Stroke Study).65 This surgical therapy tries to augment cerebral perfusion ipsilateral to carotid occlusion by connecting a temporal artery branch of the external carotid artery with the middle cerebral artery.

.

If bypass is considered, there are several measurement methods for risk stratification by hemodynamic reserve: &

Xenon-CT or single photon emission CT (SPECT) with acetazolamide (Diamox) challenge.

&

PET with oxygen extraction fraction.66

&

TCD with breath-holding index (BHI).67 .

Normal BHI 0.69 ! 20 cc;

.

drowsy but not comatose;

.

more likely if not in eloquent location.

Ventriculostomy and CSF drainage: &

May be life-saving if obstructive hydrocephalus is present.

HEMATOMA ENLARGEMENT .

Occurs in 20–35% of ICH:81 &

all locations;

&

usually in the first few hours after onset of symptoms but almost always in the first 24 hours;

Management

.

&

may occur later in patients with coagulopathy (coumadin);

&

associated with much worse prognosis.

Aggressive blood-pressure reduction to SBP 150, MAP 100–110 may reduce hemorrhage enlargement (see below). &

.

unproven (trials ongoing).

Activated factor VII (NovoSeven). &

Recent phase II trial data suggest that hemorrhage growth can be prevented by giving activated factor VII, 40–160 mg/kg.82

&

This drug (NovoSeven) is expensive and can have doserelated occlusive complications such as stroke, myocardial infarction, pulmonary embolism, etc.

&

Pending further data and recommendations, we are using this drug (80 mg/kg, single dose IV) in patients with ICH if it can be started within four hours of symptom onset or if the ICH is associated with coagulopathy (see next section). Patients with associated arterial occlusive diseases (coronary or cerebral ischemia, peripheral vascular disease, or pulmonary embolus), or who have already herniated, are not considered.

WARFARIN (COUMADIN)-RELATED INTRACEREBRAL HEMORRHAGE Goal: normal INR using fresh frozen plasma (FFP) 20 mL/kg and vitamin K* .

CT brain immediately.

.

INR, PTT, thrombin time, D-dimers, fibrinogen, CBC.

.

Type and cross, order 4 units of fresh frozen plasma (FFP).

.

Give vitamin K 10 mg IV over 10 minutes AND half of FFP (10 mL/kg). One unit of FFP ¼ 200–250 mL. Give diuretics if needed.

97


Intracerebral hemorrhage (ICH)

98


.

Repeat INR and FFP 10 mL/kg every 20–30 minutes until INR is normalized.

.

Activated factor VII (NovoSeven) (see above). Dose may be reduced to 20–40 mg/kg and repeated.

HEPARIN-RELATED INTRACEREBRAL HEMORRHAGE .

Stop heparin.

.

CT brain immediately.

.

INR, PTT, platelets, CBC, fibrinogen, thrombin time, D-dimers.

.

Type and cross.

.

Give protamine: 25 mg initial dose; check stat PTT 10 minutes later and if increased give 10 mg additionally; repeat until PTT normal.*

WHAT IS THE TARGET BLOOD PRESSURE AFTER ICH? Does lowering blood pressure cause ischemia or reduce the risk of rebleeding? .

The simple answer is that we don’t know. There is a debate as to whether there is an ischemic region around the hematoma. Various studies using various techniques have resulted in conflicting data, but the general consensus is that ischemia is not a major cause of damage except with very large hematomas. The consensus is that it is safe to lower a very high blood pressure.

.

The risk of hematoma enlargement has been associated with increasing BP, with decreased risk associated with systolic blood pressures (SBP) 150 mm Hg, but whether lowering the blood pressure reduces the risk is unknown.

Management

.

The AHA/ASA guidelines recommend mean blood pressure (MAP) goal of 130 mm Hg* but it is poor-quality evidence (level of evidence V, grade C recommendation).

80

It is possi-

ble that lower MAP (e.g., around 110 mm Hg) would result in better outcome, but this remains to be tested. .

Until we have more data, we tend to be aggressive in lowering SBP to 150 and MAP to 100–120 mm Hg in the first 12–24 hours post-ICH. &

Use titratable drugs such as nicardipine and labetalol: .

nicardipine 5 mg/hr and titrate up to 15 mg/hr as needed;

.

labetalol 10–20 mg IV bolus, repeat as needed up to 60 mg.

&

Avoid nitroprusside.

&

Other antihypertensive agents are usually not effective in the ED for accelerated hypertension associated with ICH.

ICH SUBSEQUENT CARE .

Continue to control blood pressure but maintain CPP > 70 mm Hg.

.

Goal ICP < 20 mm Hg: &

Ventricular drainage.

&

Ventricular drainage recently coupled with instillation of thrombolytics into the ventricle to accelerate ventricular clot dissolution and drainage of CSF (unproven – trials under way).

.

Maintain euvolemia, normothermia.

.

Watch for neurologic deterioration (see below).

.

Withhold all antithrombotic drugs for 2 weeks. &

Compression stockings to prevent DVT.

&

Uncertain when to start DVT prophylaxis with SC heparin or low molecular weight heparin, but probably wait at least 24 hours to be sure that no hemorrhagic enlargement is occurring and that coagulation parameters are normalized.

99


Intracerebral hemorrhage (ICH)

100


.

Talk with family about expected quality of life, advanced directives, withdrawal of support if appropriate.

.

Start working on disposition early: rehab consult, case manager.

n Prognosis and outcome NEUROLOGIC DETERIORATION IN ICH (the ranking is our impression): Cause 1: rebleeding. Cause 2: hydrocephalus (might itself be due to rebleeding). Cause 3: cerebral edema. Cause 4: general medical problems (infection, MI, electrolyte imbalance, pulmonary emboli).

ICH OUTCOME Correlates with initial GCS, size of hematoma, and presence of IVH.83 .

GCS < 9 and ICH volume > 60 cc: 90% 1-month mortality

.

GCS 9 and ICH volume < 30 cc: 17% 1-month mortality

Also see the ICH score in Appendix 14.84 .

ICH score 5: close to 100% 1-month mortality

.

ICH score 4: > 90% 1-month mortality

.

ICH score ¼ 2: 20–30% 1-month mortality

.

ICH score 1: < 15% 1-month mortality

But also remember that it can be a ‘‘self-fulfilling prophecy.’’ If one treats with the expectation that the patient will do badly, the patient will do badly.

9 Subarachnoid hemorrhage (SAH) This chapter will discuss the diagnosis and management of spontaneous subarachnoid hemorrhage due to rupture of intracranial aneurysms. The end of the chapter will also discuss unruptured intracranial aneurysms. Much SAH management is not based on good-quality evidence. Much of what is recommended here comes from published practice guidelines and what is commonly practiced.85 Options for therapy might be limited by the availability and experience of persons performing surgery, endovascular therapy, and neurointensive care.

n Definition Subarachnoid hemorrhage is bleeding into the subarachnoid space around the brain. Trauma is the most common cause of SAH. We will not discuss traumatic SAH in this chapter. This chapter will discuss spontaneous SAH, 80% of which are due to intracranial saccular aneurysms.

n Epidemiology .

3% of all strokes but 5% of stroke deaths.

.

Incidence 6–15 per 100 000 person years in the USA, with higher risk among African-Americans. Worldwide, higher incidence reported in Japan and Scandinavia.

101

Subarachnoid hemorrhage (SAH)

102


.

Females have higher incidence (60% of patients are female).

.

Risk factors: tobacco use, oral contraceptives, alcohol, and stimulants.

.

Other disease associated with aneurysms: polycystic kidney disease, Marfan’s syndrome, Ehlers–Danlos syndrome, coarctation of the aorta, fibromuscular dysplasia.

.

Location: 30% anterior communicating, 25% posterior communicating, 20% MCAs, 10% basilar, 5% vertebral, and 25% have multiple aneurysms.

n Presentation .

‘‘The worst headache of my life’’.

.

‘‘Thunder-clap headache’’.

.

Headache is sometimes associated with focal neurologic symptoms.

n Diagnosis As this condition is potentially life-threatening, diagnostic evaluation should be done emergently.

DIAGNOSIS OF SUBARACHNOID HEMORRHAGE .

CT of the head without contrast. &

If head CT is normal, but you have a high clinical suspicion for SAH, you must do a lumbar puncture, because CT can miss small or subtle SAHs, especially if more than 72 hours has passed since the ictus.

.

Lumbar puncture. &

Don’t forget to personally examine the fluid for xanthochromia. Compare the color to water. Measure red blood

Diagnosis

cells in first and last tube collected. Also, it is often helpful to personally deliver the tubes of CSF to the lab to make sure that they are processed quickly.

DIAGNOSIS OF INTRACRANIAL ANEURYSMS .

Digital subtraction angiography (DSA): the gold standard.

.

CT angiography: quite good, but depends on CT equipment. Difficult to see aneurysms near bones.

.

MRA: fair test for screening for unruptured aneurysms > 5 mm.

CAUSES OF SAH OTHER THAN INTRACRANIAL ANEURYSM .

Perimesencephalic SAH: blood limited to anterior to midbrain (or pons). Angiogram is normal. The cause of bleed is unknown (venous?). It carries a good prognosis and benign course.

.

Arteriovenous malformation (AVM): it classically causes intraparenchymal hemorrhage, but it can lead to SAH. DSA will help in diagnosis.

.

Arterial dissection (vertebral artery usually): arterial dissection that extends from the extracranial to the intracranial portion of an artery or is limited to the intracranial artery can lead to SAH. This can occur spontaneously or post-traumatic. DSA and MRI can be helpful in visualizing the abnormality.

.

Arteriovenous fistula: can be seen only with careful DSA.

.

Pituitary apoplexy: MRI is helpful in making the diagnosis.

.

Cocaine: can lead to SAH, ICH, or cerebral ischemia.

.

Trauma: detailed history or external head examination may suggest trauma as the primary cause.

.

Vasculitis: difficult to diagnose, since DSA is neither sensitive nor specific and brain biopsy is specific but insensitive.

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n Ruptured aneurysms: management GOALS .

Prevention of rebleeding.

.

Treatment of the aneurysm itself: clip or coil.

.

Prevention and treatment of complications: hydrocephalus, seizure, vasospasm, hyponatremia, infections, and DVTs.

.

Rehabilitation (see Chapter 11).

PREVENTION OF REBLEEDING Rebleeding is maximal in the first 24 hours after SAH (4%). It carries a high mortality. The following measures are often performed, but without much evidence: .

Blood pressure control may be important before definitive treatment to reduce rebleeding.

.

Bed rest in ICU with monitoring.

.

Anti-fibrinolytic drugs (epsilon amino caproic acid, tanxemic acid) reduce rebleeding but promote ischemic complications.* Consequently these drugs are rarely used.

TREATMENT OF THE ANEURYSM ITSELF It should be done as early as possible, especially in patients with mild to moderate clinical deficits, since the goal is to prevent rebleeding.

Surgical clipping* Craniotomy and placement of metal clip takes the aneurysm out of the arterial circulation.


.

It is believed to be the best way to prevent aneurysmal bleeding long-term.

.

But it carries morbidity, and some aneurysms are not amenable to clipping due to location, shape, etc.

Endovascular coiling* Coiling has become the alternative treatment. When you fill the aneurysm with coils, it thromboses, and effectively takes the aneurysm out of the arterial circulation. .

Subsequent rebleed rate is not as low as with surgical clipping, but pretty close.

.

This procedure may not be as durable as clipping. Long-term data are not available. Also, complete obliteration of the aneurysm is not always achieved initially and may require repeat intervention.

.

Some aneurysms are not amenable to coiling due to distal location or shape.

Clipping or coiling? That is the big question. .

It appears that endovascular coiling carries lower morbidity than surgical clipping.

.

ISAT was a randomized multi-center trial comparing the two methods:86 &

23.7% of coiled vs. 30.6% of clipped patients were dependent or dead at 1 year (absolute risk reduction of a bad outcome: 6.9%).

&

For this trial, the patients were required to be good candidates for both procedures (60% were treated outside the trial). 88% of patients had mild SAH (World Federation of Neurological Surgeons grade 1 or 2; see Appendix 14).

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106


&

Locations: 51% were anterior cerebral or anterior communicating artery (ACA/AcomA) and 33% were ICA or posterior communicating artery (PcomA) aneurysms. Only 14% were MCA aneurysms and 2.7% were posterior circulation aneurysms.

.

Based on ISAT, the preferred treatment of ruptured ACA, ICA, anterior or posterior communicating artery aneurysms is coiling. The preferred modality for treatment of ruptured posterior circulation aneurysm (i.e., basilar artery aneurysm) in many centers is coiling. For distal MCA aneurysms, some may be difficult to approach by coiling and need to be clipped.

PREVENTION AND TREATMENT OF COMPLICATIONS As with other strokes, general medical complications such as DVT, pneumonia, and other infection are common. SAH has particular complications that we will address here: hydrocephalus, seizure, cerebral vasospasm and delayed ischemic deficits.

Hydrocephalus Hydrocephalus occurs in 20% of patients with SAH. This may be already present at the time of presentation with SAH.

Diagnosis .

Clinical signs include a decrease in level of consciousness, agitation, hypertension, and bradycardia. However, these signs are not specific.

.

CT of head without contrast: enlargement of ventricles.


Treatment .

External drainage of CSF via intraventricular catheter (ventriculostomy or external ventricular drain).

.

Ventriculostomy must be monitored for amount of CSF drained and for infection.

.

If hydrocephalus is persistent, CSF drainage can be converted to internal drainage by placement of ventriculo-peritoneal, ventriculo-atrial, or lumbo-peritoneal shunt by a neurosurgeon.

Seizure Seizure may increase blood pressure and may increase rebleeding risk.

Prevention .

Without good evidence for efficacy, the current practice is to routinely administer antiepileptic agents to prevent seizures.

.

Phenytoin 300 mg per day and adjusted to maintain level of 10–20 mg/mL.

Diagnosis .

Non-convulsive seizure may go unrecognized. Bedside EEG may help if SAH itself or sedative drugs affect assessment.

Treatment .

Phenytoin is most commonly used and is available in intravenous and oral formulations. Among other anticonvulsants, valproic acid and phenobarbital are available in IV formulation.

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Cerebral vasospasm and delayed ischemic deficits .

Onset usually 3–5 days after SAH, maximal at 5–10 days.

.

30% of SAH patients develop vasospasm, and 15–20% go on to have ischemic strokes.

Prevention .

Calcium channel blockers: nimodipine (Nimotop) 60 mg PO every 4 hours 3 weeks*, but adjust dose downwards if blood pressure falls so low that adequate CPP is endangered. This should be started early after diagnosis of SAH to prevent vasospasm.

.

Magnesium: phase II data suggest that magnesium sulfate started within 4 days after SAH and given continuously until 14 days after aneurysm treatment may reduce delayed ischemic deficits.87 The dose used was magnesium sulfate 64 mmol/L per day with aim of magnesium level of 1.0–2.0 mmol/L.

Diagnosis .

TCD: Velocity trend with daily or sequential measurements is more useful than one-time snapshot of velocities. So get a baseline and follow daily. Lindegaard ratio is the velocity ratio of MCA to extracranial ICA. Increasing flow velocity may indicate either vasospasm or overall increased blood flow. Increasing Lindegaard ratio may be more reliable sign of MCA vasospasm.

.

CTA: CT angiography requires iodine contrast injection but may be combined with CT perfusion to diagnose vasospasm and ischemia.

.

Angiography: more invasive, but can also be linked to treatment with angioplasty or intra-arterial papaverine.

Admission sequence

.

Clinical symptoms and signs: similar to ischemic stroke, though in addition may have bilateral frontal lobe dysfunction in the case of anterior communicating artery vasospasm. You want to diagnose and treat vasospasm before these symptoms and signs develop.

Treatment .

Hypertension–hypervolemia–hemodilution (HHH): commonly used. Combination of pressors and volume expanders such as albumin, synthetic starches, colloid, blood.

.

Direct endovascular treatment can be performed with balloon angioplasty or drug infusion of papaverine or nicardipine.

n Prognosis Mortality: in a population-based study, 3% died before reaching medical attention and one-third died in the first month.88 A quarter of the deaths are attributable to initial bleed directly, another quarter to vasospasm, and another quarter to rebleeding. .

Morbidity: one-third had neurologic deficit.

.

Rebleeding risk: with unclipped aneurysm, 6% rebleed within first 3 days, and 12% in the first 2 weeks.89 Hypertension increases chance of rebleeding.

n Admission sequence Since these patients are usually admitted to Neurosurgery, we are not providing sample admission orders, but do provide the usual sequence of events upon admitting a patient with SAH.

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Table 9.1. One-month outcome after SAH by clinical status at presentation, a population-based study.88

Clinical status at presentation Hunt & Hess scale

Grade I Grade II Grade III Grade IV Grade V

Glasgow coma scale

13–15 9–12 3–8

Poor outcome (severe neurologic deficits, vegetative, or dead)

Relative risk of poor outcome (95% CI)

22% 22% 50% 87% 100%

1 1.0 (0.4–2.2) 2.2 (1.1–10.9) 3.9 (2.3–7.8) 1

24% 84% 97%

1 3.6 (2.4–5.2) 4.1 (2.9–5.8)

Source: W. T. Longstreth Jr., L. M. Nelson, T. D. Koepsell, & G. van Belle, Clinical course of spontaneous subarachnoid hemorrhage: a population-based study in King County, Washington. Neurology 1993; 43: 712–18.88 Reproduced with permission from Lippincott Williams & Wilkins.

.

Establish diagnosis of SAH with CT or lumbar puncture as soon as possible.

.

Neurosurgery consult, admission to ICU. &

If necessary, transfer emergently to an appropriate hospital that has adequate neurosurgical, neurointerventional (coiling), and neurocritical care capability.

&

.

Consider ventriculostomy if hydrocephalus is present.

Determine location of ruptured aneurysm with CT angiogram or digital subtraction angiography (do in the first day).

.

Definitive aneurysm treatment (coiling or clipping).


.

Nimodipine per nasogastric tube.

.

Watch for vasospasm (first 2 weeks).

n Unruptured aneurysms Unruptured aneurysms are sometimes found incidentally as part of brain imaging or due to neurologic symptoms other than rupture and SAH. Some patients with SAH are found to have other aneurysms that have not ruptured. Some unruptured aneurysms are found due to screening of those with family history of SAH.

DIAGNOSIS The diagnostic strategy is the same as for ruptured aneurysms, with DSA being the gold standard for accurate diagnosis and measurement of an aneurysm. CT angiography and MRA are fair screening tools.

NATURAL HISTORY 0.5–1% of the general population harbor unruptured intracranial aneurysms. Controversy exists among experts about the natural course and decision to intervene.90,91

ISUIA study .

The rupture rates were higher for aneurysms of larger size, in the posterior circulation (posterior communicating, posterior cerebral, vertebral, or basilar artery), and in patients with a history of previous SAH.

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112


.

Among those with no history of SAH: &

bleed rate 0.1% per year if 3% per year if >12 mm diameter.

Other observational studies .

1–2% per year.

The controversy and uncertainty of management depends on the paradoxical observation that despite the low rates of rupture of small aneurysms when followed over time, most subarachnoid hemorrhages are due to small aneurysms.

MANAGEMENT Decision to clip or coil an unruptured aneurysm depends on five main factors: .

Previous history of bleeding – increases risk of recurrence and weighs in favor of intervention, either clipping or coiling.

.

Aneurysm location – anterior circulation has less rupture risk and has less surgical morbidity.

.

Aneurysm size – unruptured aneurysms larger than 7 mm are more likely to bleed.

.

Patient age – increased morbidity with any intervention with increased age. Morbidity risk associated with coiling appears to be less dependent on age.

.

Surgical experience – perioperative and peri-coiling morbidity is lower in experienced hands.

Treatment decisions for each patient must be individualized by neurology, neurosurgery, and endovascular consultants based


on these five variables. We are awaiting definitive data from ongoing trials that will provide more information to assist in our decisions, but the following are ‘‘general’’ recommendations: .

Unruptured aneurysm cavernous or < 5–7 mm: leave alone.

.

Unruptured aneurysm > 7 mm, anterior circulation, patient < 65 years old, experienced surgeon/center: surgical clipping.

.

Unruptured aneurysm > 7 mm, posterior circulation, patient > 65 years old, experienced endovascular team: coiling.

113


10 Organization of stroke care

As stroke therapies develop, the context in which stroke care is provided is becoming more important. Creating and maintaining a good organization of stroke care within a region or even a hospital requires much commitment and effort. The European Stroke Initiative provides a good set of evidencebased recommendations.92,93 An American Stroke Association task force recently published a set of recommendations on systems of stroke care.94

n Timely care Time is emerging as an important factor in improving outcome. IV TPA must be given within 3 hours, with better results the earlier it is administered. Most investigational stroke therapies for both ischemic and hemorrhagic strokes are focusing on early therapies. A number of important points arise: .

Promotion of public awareness. Patients, family and the general public must be educated regarding stroke symptom recognition, available stroke therapies, and the importance of emergency medical care.

.

Education of prehospital providers. Dispatch personnel, ambulance drivers, emergency medical technicians,

114

Stroke units

paramedics, and their medical supervisors must agree to prioritize acute stroke and train to increase stroke recognition. .

Coordination of speedy triage and evaluation. Acute stroke patients must be evaluated in a timely fashion, and preferentially transported to a stroke center if one is available. In Houston, prehospital providers notify the receiving facility or stroke team directly and shorten the time to evaluation. Emergency department physicians should evaluate immediately after patient arrival. Stroke team members should be notified at the earliest yet most practical time possible.

.

Stroke team. The establishment of a specialized stroke team helps in concentrating expertise and improving the availability of acute stroke care.

n Stroke units Specialized stroke units have been shown to improve outcome.95* Therefore, all acute stroke patients should ideally be admitted to a stroke unit. Some uncertainty exists regarding what features of the stroke unit are important. .

Comprehensive stroke units should have trained nurses, therapists (physical, occupational, speech), and physicians acting in a multidisciplinary approach. This type of stroke unit has been shown to improve outcome.*

.

Acute stroke care units in the North American model can take care of TPA-treated patients. This includes frequent monitoring of vital signs, cardiac rhythm monitoring, and the ability to administer some intravenous antihypertensive drugs.

115


Organization of stroke care

116


n Stroke centers Whenever possible, stroke patients should be treated in hospitals with the ability to deliver stroke therapy. It is important to foster the development of such ‘‘stroke centers’’. This may involve the need to establish a regional organization of stroke care. .

Primary stroke centers. There is a need for the establishment of facilities that can provide good basic acute stroke care, with acute stroke teams, stroke units, and ability to administer IV TPA. In the USA the Brain Attack Coalition has published criteria for primary stroke centers,96 and the Joint Commission on Accreditation of Healthcare Organizations has started accreditation of primary stroke centers (www.jointcommission.org).

.

Comprehensive stroke centers would have advanced capability with availability of interventionalists and neurosurgeons.

.

Quality assurance measures such as written protocols, and performance measurements should be part of stroke centers.

n Stroke teams Acute stroke teams help provide the above care based on the latest evidence-based guidelines. The team might consist of neurologists, internists, emergency department physicians, neurosurgeons, intensivists, rehabilitation physicians, endovascular neurointerventionalists, ultrasonographers, nurses, therapists, dieticians, patient care managers, smoking cessation counselors, stroke educators, etc. Stroke care should be optimized to meet the needs of the local region and institution.

Stroke teams

.

Acute stroke care might be provided by a mobile stroke team going to different hospitals in a city or region.

.

Care might be enhanced by providing streamlined access to a central stroke center.

.

In rural areas where physicians with expertise in stroke are often many miles away, consultation by telephone or with advanced telecommunication methods might allow safe administration of thrombolytics locally and facilitate transfer to a stroke center.

117


11 Rehabilitation

Stroke rehabilitation begins during the acute hospitalization once the patient is medically and neurologically stable. Rehabilitation of the stroke patient with involvement of a multidisciplinary rehabilitation team early during the care of the stroke patient is one of the critical components of stroke unit care that results in improved outcome and shortened length of stay. While practices vary between countries and among hospitals, at our hospital and most stroke centers in the USA the major focus of rehabilitative efforts occurs after the stay in the acute stroke unit, and is beyond the scope of this book. We will focus on those aspects of rehabilitation care that are relevant to acute stroke management in the USA. The primary goals of rehabilitation are to prevent complications, minimize impairments, and maximize function. The priorities of early stroke rehabilitation are secondary stroke prevention, management of comorbidities and prevention of complications. The principles of rehabilitation are the same in patients with cerebral infarction and in those with hemorrhage.

TAKE-HOME MESSAGES

118

.

Adequate secondary stroke prevention regimen.

.

Prevention of medical complications.


.

Early assessment of rehabilitation needs, utilizing a multidisciplinary rehabilitation team.

.

Early initiation of rehabilitation therapies, and greater intensity of therapy, as tolerated by the patient.

n Secondary stroke prevention Please see Chapter 6 for detailed discussion.

n Prevention of medical complications Please see Appendix 9 for detailed discussion.

n Multidisciplinary rehabilitation team The main components of the rehabilitation team are speech therapy, physical therapy, occupational therapy, and psychosocial therapy.

SPEECH THERAPY (ST) Speech therapy in the stroke unit has two main components: assessment of swallowing and assessment of language function.

Swallowing The need for swallowing assessment has already been addressed in describing the routine care of the patient with infarct and hemorrhage (Chapter 3). Dysphagia (difficulty with swallowing) is common, occurring in 30–65% of post-stroke

119


120


Rehabilitation

patients.97 Dysphagia may cause malnutrition, dehydration, and aspiration pneumonia. A bedside swallowing screen should be carried out in all patients before allowing them to eat. If patients are unable to swallow effectively within 12–24 hours, a nasogastric tube (NGT) should be placed for enteral feeding. In fully conscious patients with hemispheric stroke, generally, this can be removed and the patient fed by mouth within several days. If there is any question, a modified barium swallow (MBS) should be completed to assess for aspiration and the patient’s ability to safely swallow food and liquids of varying consistencies. However, many stroke patients have prolonged dysphagia. Most often this occurs in patients with brainstem strokes or with hemispheric stroke associated with depressed level of consciousness, dementia, or confusion. In these cases, a percutaneous endoscopic gastrostomy (PEG) tube should be placed. Generally, we wait 5 days or so after the stroke before deciding to place a PEG, though in patients who will obviously need one, there is no reason to wait. Begin the process of planning for a PEG early since it takes several days to arrange. Antiplatelet or anticoagulation therapy will raise concerns of bleeding risk and should be addressed as early as possible so as not to delay PEG placement. In our hospital, the procedure can be done by gastroenterologists, general surgeons, or interventional radiologists.

Language A description of the different aphasic syndromes is beyond the scope of this book. Most stroke patients have non-fluent-type aphasias, where their speech output is reduced or absent, with comprehension being variably affected. It is less common to see pure fluent aphasias affecting only comprehension, though


this certainly can occur. Aphasia, especially impaired comprehension, can seriously impede other aspects of rehabilitation since the patient often cannot understand commands of therapists. As with other aspects of stroke recovery, practice and time with ST will result in at least some improvement in language function, with comprehension usually improving first. Pharmacotherapy with amphetamines, cholinergic, and dopaminergic agents may provide benefit for particular aphasic syndromes but is unproven. The patient’s and the family’s frustration with impaired ability to communicate should be dealt with in a supportive manner until improvement begins to occur.

PHYSICAL THERAPY (PT) Physical therapy focuses on bed mobility, transfers, balance, gait training, training to regain normal movement patterns, and wheelchair mobility. Generally, gait training is not begun in earnest until the patient moves off the stroke unit and onto the rehabilitation unit. In the first few hours after stroke, especially if the patient is fluctuating, we recommend bed rest, keeping the head no higher than 15–308 in order to optimize cerebral perfusion. At the same time, early mobilization is important to prevent deconditioning and deep venous thrombosis. Therefore, we often qualify the bed rest order to allow the patient up with physical therapy and nursing attendance. When the patient first gets up in these cases, the physical therapist and nurse should be instructed to measure the blood pressure before and after sitting and standing, and to maintain careful neurological monitoring, to be sure that the blood pressure doesn’t fall or the patient deteriorate.

121


122


Rehabilitation

In the stroke unit, the day following admission, the physical therapist will begin to deal with sitting and transferring from bed to chair, and then standing by the bedside. It is important to remember that patients may have impaired balance and generalized weakness, even if they don’t demonstrate a hemiparesis or other signs of weakness or ataxia when lying in bed. Therefore, every stroke patient should be considered a fall risk when they first get out of bed and should not be allowed up unassisted until evaluated by PT. This occurs for several reasons. Even a day or two lying in bed can result in a general deconditioning that can lead to generalized weakness and orthostatic hypotension. This can be aggravated by antihypertensive and other medications that are well tolerated when the patient is lying flat, but can cause orthostatic changes when the patient gets out of bed. 80% of stroke patients will eventually regain their ability to walk independently, so that tempered optimism is a reasonable approach when dealing with patients and families in the first few days, even in the case of those with hemiplegia.

OCCUPATIONAL THERAPY (OT) Occupational therapy focuses on fine and gross motor coordination (pinch, opposition, finger to nose, rapid alternating movements), strength (active range of motion, passive range of motion), tone, sensation, activities of daily living (grooming, bathing, upper extremity dressing, lower extremity dressing, commode transfer, toileting) and training to regain normal movement patterns. Various assistive devices such as braces and splints may be used to help with supporting weak limbs, stabilizing joints, and avoiding contractures and pressure sores caused by spasticity


and immobility. Larger more easily grasped appliances can be used to augment the functional use of a weak limb. The use of these devices is beyond the scope of this chapter. An important principle of OT is compensation vs. facilitation. Put simplistically, compensation refers to training the unaffected limb to compensate by carrying out functions of the impaired limb, while facilitation refers to repetitive use of the affected limb in order to accelerate recovery and avoid ‘‘learned non-use’’ that might result from over-compensatory reliance on the unaffected limb. Recent animal and human brain mapping studies have shown unexpected cortical plasticity in areas adjacent to the stroke, and even contralateral brain areas, in response to repeated attempts to move an affected limb or digit or, in the case of an aphasic patient, to talk. The observation of increased metabolic activity in these areas not normally associated with the function of the affected limb or language has stimulated renewed interest in early and intensive rehabilitation efforts.

PSYCHOSOCIAL EVALUATION It is never too early to begin to educate the patient and family about lifestyle changes and medical treatments to prevent another stroke. These need to be reinforced throughout the hospital and rehabilitation stay. After a major stroke, both the family and the patient go through a grief reaction which at first includes denial and disbelief, and sometimes anger. In particular, the need to insert a PEG is often a crisis point when the family finally comes to terms with the severe disability and prolonged recovery that lies ahead. At this stage, which is usually when the patient is in the acute stroke unit, mainly supportive measures are

123


Rehabilitation

124


indicated. More detailed teaching and coping with the consequences of the disability usually waits until after the acute stroke stay when the realities of the impairment become more clear, and the shock, disorientation, and confusion have worn off. Even in patients fully recovering from their stroke, the threat of another event and the realization of vulnerability usually cause significant emotional consequences. Depression in the patient and caregiver are common. Incontinence is an important contributor to depression and dependence, in addition to the obvious other causes (paralysis, inability to talk, and pain). Pre-morbid depressive tendencies are often amplified after a stroke, so that even patients with little disability may become depressed. Stroke location may also play a role, with more depression reported in nondominant frontal lesions. Depressed patients often respond well to pharmacotherapy, but again, these psychosocial issues are usually addressed after the acute stroke stay. The most pressing psychosocial issues to consider in the first few days after stroke onset concern the management of either confusion/delirium or decreased level of arousal.

Delirium Management of the confused and delirious patient with choice of sedating drugs has been addressed in Chapter 5. Basic rules: .

Sedate only when necessary. &

Avoid benzodiazepines.

&

Haloperidol (Haldol) 0.5–4 mg PO or IV every 6 hours, risperidone (Risperdal) 0.5–1 mg PO at bedtime or twice daily, quetiapine (Seroquel) 25–50 mg PO once or twice daily, and ziprasidone (Geodon) 10–20 mg IM/PO once or twice daily are probably best.

.

Use soft restraints and move to a private room if possible.


Level of arousal Decreased level of arousal is commonly seen in large hemispheric strokes, and often impedes participation in rehabilitation. Such patients may benefit from activating or stimulant drugs. Pharmacotherapy is usually not initiated before a week post-stroke. It is important to be sure that the patient is not sleepy due to metabolic abnormalities or increased ICP (see Chapter 5).

Amantadine (Symmetrel) .

Dosage: 100 mg morning and noon (initial).

.

Contraindications: epilepsy, any seizure disorder, congestive heart failure or accumulation of fluid (swelling) in arms, legs, hands, or feet, kidney disease, liver disease, chronic rash such as eczema.

.

Side effects: headache, nausea or decreased appetite, depression, anxiety or confusion, insomnia, nervousness, dizziness, lightheadedness, drowsiness, dry mouth, constipation.

.

Close monitoring if on a diuretic.

Mondafinil (Provigil) .

Dosage:100 mg morning (initial).

.

Contraindication: angina, recent MI, cirrhosis, seizures.

.

Side effects: headache, nausea, anxiety, insomnia, nervousness, dizziness.

Methylphenidate (Ritalin) .

Dosage: 5 mg morning and noon (initial).

.

Contraindications: marked anxiety, tension and agitation, patients with glaucoma, seizures, motor tics, not in combination with a monoamine oxidase inhibitor.

125


Rehabilitation

126


.

Side effects: anxiety, insomnia, nervousness, hypersensitivity reactions, anorexia, dizziness, palpitations, blood pressure alterations, cardiac arrhythmias.

.

Serious adverse events reported with concomitant use with clonidine.

Bromocriptine (Parlodel) .

Dosage: 1.25 mg morning and noon (initial).

.

Contraindication: uncontrolled hypertension.

.

Side effects: nausea, headache, dizziness, fatigue, vomiting, drowsiness.

n Discharge planning Patients will either go home, to long-term acute care, to inpatient rehabilitation, to a skilled nursing facility, or to a nursing home. This should be determined after evaluating the patient’s short- and long-term rehabilitation potential in conjunction with the rehabilitation team, and discussions with the patient and family over resources, home support and environment, and preferred location.

HOME For the patient who is independent. Consider home safety evaluation, supervision level, and arrange outpatient rehabilitation services if needed.

LONG-TERM ACUTE CARE (LTAC) For the patient who has medical needs requiring long-term hospitalization, usually for more than a month. An example

Discharge planning

would be a patient with pneumonia after a tracheostomy and PEG, or patients with other critical care or medical needs that make them too sick for an inpatient rehabilitation unit or a nursing facility because daily medical care is needed.

INPATIENT REHABILITATION Rehabilitation completed during an inpatient stay in a rehabilitation unit of an acute care hospital, or in a freestanding rehabilitation hospital. For patients who have good rehabilitation potential but who are not yet able to function independently at home. Must be alert, cooperative, and strong enough to be able to participate in 3 hours of PT and OT daily. Medicare criteria are that patients must be able to tolerate 3 hours of therapy daily, and must require two modalities of therapy, of which one is PT. Usually lasts for 2 weeks.

SKILLED NURSING (SNF) Rehabilitation performed during a stay in a nursing facility. For patients at a lower level than inpatient rehabilitation, these are patients who are not yet able to function independently at home, and can’t participate in 3 hours of therapy daily, but do have the potential for improving to that point over the next few months. These patients must be medically stable. If needed, tracheostomy and PEG should be done before transfer. Nursing facilities vary widely in the delivery of rehabilitation services, from limited services to complete range of rehabilitation services (OT, PT, ST).

127


128


Rehabilitation

NURSING HOME For patients who are dependent for most of their daily needs, and likely to stay that way. These patients must be medically stable. Usually a PEG does not exclude a patient, but a tracheostomy and the need for frequent suctioning means the patient will need an SNF.

Appendix 1 Numbers and calculations

Weight 1 pound ¼ 0.4535924 kilograms 1 kilogram ¼ 2.204622 pounds

Pressure 1 mm Hg ¼ 1.36 cm H20 1 cm H20 ¼ 0.74 mm Hg

Mean arterial pressure (MAP) SBP þ ðDBP 2Þ 3 Normal MAP 70–105 mm Hg

Intracranial pressure (ICP) Normal < 10–15 mm Hg


130


Numbers and calculations

Calculating ICH volume on a CT image. Source: J. P. Broderick, T. G. Brott, J. E. Duldner, T. Tomsick, & G. Huster, Volume of intracerebral hemorrhage: a powerful and easy-to-use predictor of 30-day mortality. Stroke 1993; 24: 987–93.83 Reproduced with permission from Lippincott Williams & Wilkins.

Cerebral perfusion pressure (CPP) CPP ¼ MAP – ICP Normal CPP 70–100 mm Hg Goal CPP > 70–80 mm Hg

Hemorrhage volume calculation Lengths in cm: .

A and B are perpendicular diameters at the level of the largest hematoma area

.

C is the thickness of the hematoma ¼ (number of CT slices

.

Do not include intraventricular blood.

with visible hematoma) (thickness of slice)

Volume in mL ðcm3 Þ A B C 2

Appendix 2 IV TPA dosing chart Patient weight

Pounds 99 lb 101 lb 104 lb 106 lb 108 lb 110 lb 112 lb 115 lb 117 lb 119 lb 121 lb 123 lb 126 lb 128 lb 130 lb 132 lb 134 lb 137 lb 139 lb 141 lb 143 lb 146 lb 148 lb 150 lb 152 lb

Kilograms 45 kg 46 kg 47 kg 48 kg 49 kg 50 kg 51 kg 52 kg 53 kg 54 kg 55 kg 56 kg 57 kg 58 kg 59 kg 60 kg 61 kg 62 kg 63 kg 64 kg 65 kg 66 kg 67 kg 68 kg 69 kg

TPA dose (mg)

Total

Bolus over 1 minute

Infusion over 1 hour

41 41 42 43 44 45 46 47 48 49 50 50 51 52 53 54 55 56 57 58 59 59 60 61 62

4.1 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5.0 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 5.9 6.0 6.1 6.2

37 37 38 39 40 41 41 42 43 44 45 45 46 47 48 49 50 50 51 52 53 53 54 55 56


132


IV TPA dosing chart

Patient weight

TPA dose (mg)

Pounds

Kilograms

Total

Bolus over 1 minute

Infusion over 1 hour

154 lb 157 lb 159 lb 161 lb 163 lb 165 lb 168 lb 170 lb 172 lb 174 lb 176 lb 179 lb 181 lb 183 lb 185 lb 187 lb 190 lb 192 lb 194 lb 196 lb 198 lb 201 lb 203 lb 205 lb 207 lb 209 lb 212 lb 214 lb 216 lb 218 lb 220 lb

70 kg 71 kg 72 kg 73 kg 74 kg 75 kg 76 kg 77 kg 78 kg 79 kg 80 kg 81 kg 82 kg 83 kg 84 kg 85 kg 86 kg 87 kg 88 kg 89 kg 90 kg 91 kg 92 kg 93 kg 94 kg 95 kg 96 kg 97 kg 98 kg 99 kg 100 kg

63 64 65 66 67 68 68 69 70 71 72 73 74 75 76 77 77 78 79 80 81 82 83 84 85 86 86 87 88 89 90

6.3 6.4 6.5 6.6 6.7 6.8 6.8 6.9 7.0 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.7 7.8 7.9 8.0 8.1 8.2 8.3 8.4 8.5 8.6 8.6 8.7 8.8 8.9 9.0

57 58 59 59 60 61 61 62 63 64 65 66 67 68 68 69 69 70 71 72 73 74 75 76 77 77 77 78 79 80 81

Note: Patients weighing more than 100 kg (220 lb) receive 90 mg (9 mg bolus and 81 mg infusion).

Appendix 3 Sample admission orders Routine ischemic stroke STAT “ PLACE X IN BOX IF STAT ” ALLERGIES:

NKA

“Authorization is hereby given to dispense the Generic equivalent or Medical Staff approved therapeutic equivalent unless otherwise indicated by the wordsDO NOT SUBSTITUTE – MEDICAL NECESSITY”

YES

DRUG:__________________ OTHER: _________________ WT: _____________kg HT: ____________cm

Date

Time

PHYSICIAN’S ORDERS Admit to Dr.__________________________________ NTICU Stroke Unit NIMU Floor Diagnosis: _________________________________ Guarded Critical Condition: Stable Vitals:

Vital signs and neuro check every 1 hour × 4 hours, then q 2 hours × 8 hours, then routine Vital signs every________________hours Neuro checks every______________ hours Ins and Out qshift

Call Orders: Notify physician for the following: Change in neuro status MAP > _______mmHg or _______ (200) mmHg or < ________mmHg DPB > _______ (120) mmHg or < ________ (50) mmHg Respiratory rate >________(24) or < _________(8) Heart rate > ________(120) or < _______(50) Temperature > _______(101.4)°F or _________ml/hr or < ________ml/hr Foley catheter (MRI compatible):

Yes

No

Straight catheterization if unable to void

Activity: Bed rest Up in chair_________ Head of bed 30° and initiate aspiration precautions Head of bed flat × ______ hours OOB with PT/OT Bathroom privileges with assistance Diet: NPO until cleared by Speech Speech consult Regular ADA _________________calories Other ___________________________________ IV Fluids: Saline lock 0.9NS + 20 mEq KCl/liter @ ______ml/hr × _______L then saline lock OR call HO for further orders Other: __________________________________________________ Laboratory (if not already done): Chem-12 Liver profile CBC with platelets Urine culture and urinalysis PT/INR/PTT Fasting lipid profile Hemoglobin A1C Other________________________ _______________________ _________________ _________________ Name Print Pager No./MSID #

_________________ Date/Time


134


Sample admission orders

Acute Ischemic Stroke Orders

Please place patient sticker here

(Page 1 of 2)

STAT “ PLACE X IN BOX IF STAT ” ALLERGIES:

NKA

YES


Date

Time


PHYSICIAN’S ORDERS Respiratory: O2 per________at _________l/min. Titrate Q______hour to maintain O2 sat ≥ ______(92)%. Check O2 sat on room air every 8 hours; may discontinue O2 if sat ≥ 92% on 3 readings. Albuterol 2.5 mg Q______(6) hours and Q __________(2) hours PRN wheezing. Ipratroprium bromide 0.5 mg neb Q ______(8) hours. Indicated in COPD. Diagnostic Studies: CT of head (noncontrast) @_______________ Exam: Brain MRI Contrast MRA Indication:_________________________________ Order Comments: Perfusion ICH protocol MRV Perfusion and ICH require contrast. List neurological sign or symptom for indication:________________ Carotid doppler ultrasound CT angiogram of head and neck to include vertebral origins. Indication:__________________ Transcranial doppler 2-D ECHO with bubble study Indication:___________________ 12-lead EKG Indication:__________________ TEE Indication:________________________

Antiplatelets: Aspirin loading dose _______ mg PO × 1. (Do not give if administered in ED) Aspirin________mg PO daily Clopidogrel (Plavix)loading dose______ mg PO × 1. (Do not give if administered in ED) Clopidogrel (Plavix) 75 mg PO every day. Dipyridamole 200mg/aspirin 25mg (Aggrenox) 1 tablet PO every 12 hours.

Antihypertensives: If SBP >__________mmHg or DBP>________mmHg, give: Labetalol 10– 20 mg IV over 1–2 minutes every 15 minutes × 3 Do not give if SBP 70 kg.Platelet count every other day starting on Day 2 Enoxaparin (Lovenox) ______(30) mg SQ Q________(12) hours. For renal impairment use 30–40 mg SQ every day. Platelet count every other day starting on Day 2

_________________________ Name

_________________ _________________ Print Pager No./MSID #

_________________ Date/Time


Acute Ischemic Stroke Orders (Page 2 of 2)


NKA

YES


Date

Time



PHYSICIAN’S ORDERS Blood Glucose Therapy: FSBG every 4 hours. Administer Regular human insulin SQ. Blood Glucose Repeat FSBG; If < 60 mg/dl, give 50 ml D50W IV and call HO, repeat FSBG ≤60 mg/dl in 15 minutes 61–110 mg/dl Do not administer insulin 111–125 mg/dl 3 units 126–150 mg/dl 5 units >150 mg/dl 7 units, call HO for 2 consecutive FSBG > 150 mg/dl Laxative Therapy: Docusate sodium 100 mg PO every 12 hours. Bisacodyl 10 mg suppository PR every day PRN. Milk of Magnesia 30–60 m lPO PRN if no results from bisacodyl. Stress Ulcer Prophylaxis: Famotidine (Pepcid) 20 mg PO OR IV every 12 hours. Circle route. Analgesic/Antipyretic Therapy: Acetaminophen 650 mg PO OR PR every 4 hours PRN temperature greater than 101.5° F Circle route. Cooling blanket Rehabilitation: Stroke Rehab (advise patients with ongoing neurological deficits) Physical therapy Occupational therapy Nutrition consult Speech therapy Chaplain consult PM&R Discharge Planning: Financial Counselor consult

Other Orders: _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________

_________________________ Name


_________________ Date/Time

135


136



Post-TPA STAT “ PLACE X IN BOX IF STAT ” ALLERGIES:

NKA


YES


Date

Time

PHYSICIAN’S ORDERS Admit to Dr.__________________________________ NTICU Stroke Unit NIMU Floor Diagnosis: _________________________________ Stable Guarded Critical Condition: Vitals:

Vital signs and neuro check every 1 hour × 4 hours, then q 2 hours × 8 hours, then routine Monitor BP q15 minutes × 2 hours, q30 minutes × 6 hours, then q1hour × 16 hours Telemetry × 24 hours Neuro checks every______________ hours Ins and Out qshift

Call Orders: Notify physician for the following: Change in neuro status Angioedema Signs and symptoms of bleeding MAP > _______mmHg or _______ (180) mmHg or < ________mmHg DPB > _______ (105) mmHg or < ________ (50) mmHg Respiratory rate >________(24) or < _________(8) Heart rate > ________(120) or < _______(50) Temperature > _______(101.4)°F or _________ml/hr or < ________ml/hr Foley catheter (MRI compatible):

Yes

No

Straight catheterization if unable to void

Activity: Bed rest × 24 hours except for PT,OT, Rehab evaluation Head of bed flat × 12 hours Avoid arterial sticks and other procedures that may increase risk of bleeding × 24 hours Diet: NPO until cleared by Speech Speech consult Regular ADA _________________calories

Other:_____________________________

IV Fluids: Saline lock 0.9NS + 20 mEq KCl/liter@ ______ml/hr × ____L then saline lock OR call HO for further orders Other: __________________________________________________ Laboratory (if not already done): Chem-12 CBC with differential and platelets Urine culture and urinalysis PT/INR/PTT Fasting lipid profile Hemoglobin A1C Liver profile Other:_____________________________ ________________________ _________________ _________________ _________________ Name Print Pager No./MSID # Date/Time


Acute Ischemic Stroke Orders: Post t-PA


(Page 1 of 2)


NKA

YES


Date

Time


PHYSICIAN’S ORDERS Respiratory: O2 per________at _________l/min. Titrate Q______hour to maintain O2 sat ≥ ______(92)%. Check O2 sat on room air every 8 hours; may discontinue O2 if sat ≥ 92% on 3 readings. Albuterol 2.5 mg Q______(6) hours and Q __________(2) hours PRN wheezing. Ipratroprium bromide 0.5 mg neb Q ______(8) hours. Indicated for COPD. Diagnostic Studies: CT of head (noncontrast)@_______________ Exam: Brain MRI Contrast MRA Indication:_________________________________ Perfusion ICH protocol MRV Order Comments: Perfusion and ICH require contrast. List neurological sign or symptom for indication:________________ Carotid doppler ultrasound CT angiogram of head and neck to include vertebral origins. Indication:__________________ Transcranial doppler 2-D ECHO with bubble study Indication:___________________ 12-lead EKG Indication:__________________ TEE Indication:________________________ Antihypertensives: If SBP >__________mmHg or DBP>________mmHg, give: Labetalol 10–20 mg IV over 1–2 minutes every 15 minutes × 3 Do not give if SBP 150 mg/dl 7 units, call HO for 2 consecutive FSBG > 150 mg/dl Laxative Therapy: Docusate sodium 100 mg PO every 12 hours. Bisacodyl 10 mg suppository PR every day PRN. Milk of Magnesia 30–60 ml PO PRN if no results from bisacodyl. Stress Ulcer Prophylaxis: Famotidine (Pepcid) 20 mg PO OR IV every 12 hours. Circle route. Analgesic/Antipyretic Therapy: Acetaminophen 650 mg PO OR PR every 4 hours PRN temperature greater than 101.5 °F Circle route. Cooling blanket Rehabilitation: Stroke Rehab (advise patients with ongoing neurological deficits) Physical therapy Occupational therapy Nutrition consult Speech therapy Chaplain consult PM&R

Discharge Planning: Financial Counselor consult

Other Orders: _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________

_________________________ Name


_________________ Date/Time

Appendix 4 Sample discharge summary

Name Medical record number Admitting date, service, and attending physician Discharge date, service, and attending physician (if different from admission) Discharge diagnosis Be specific regarding type and cause of stroke, and include risk factors and other important diagnoses, e.g. (1) cardioembolic ischemic stroke (2) atrial fibrillation (3) hypertension History of present illness .

Presenting symptoms (be specific, including time of onset)

.

Past medical history

.

Past surgical history

.

Medications on admission

.

Relevant social history

.

Relevant family history

.

Relevant review of systems


140


Sample discharge summary

.

Physical exam &

Include general exam as well as neurologic exam

&

Include NIH stroke scale if possible

.

Labs

.

Radiology

.

Procedures

.

Consults

Hospital course .

Include acute treatment, diagnostic work-up, neurologic course, complications

.

Stroke mechanism &

For ischemia: cardioembolic, carotid stenosis, intracranial stenosis, lacunar stroke, dissection, venous, cryptogenic, etc.

&

For ICH: hypertensive, AVM, amyloid angiopathy, unknown, etc.

.

.

Condition at discharge: stable, etc. &

Also describe remaining deficits, impairment

&

Discharge NIH stroke scale

Disposition: home, skilled nursing facility, inpatient rehabilitation, etc.

.

Discharge medications

.

Instructions to patients &

Physical activity

&

Diet

&

Smoking cessation counseling, etc.

&

Follow-up plan

Send copy to primary care provider.

Appendix 5 Stroke radiology

COMPUTED TOMOGRAPHY (CT) Non-contrast head CT remains the standard procedure for initial evaluation of stroke.

Acute ischemia appearances (general guidelines) .

1.5 hours: loss of grey–white differentiation

.

>3 hours: hypodensity

.

>6 hours: swelling

.

>weeks: ex-vacuo changes

Window width and level (WW/WL) for early CT The standard brain view on CT is set at around 90/40. Setting of 25/30 may give high contrast of brain parenchyma to demonstrate the early ischemic signs more easily.

Acute hemorrhage (extravasated blood) Appears hyperdense (bright) in 40–60 Hounsefield units (HU). In the first few hours, the intensity may increase to 60–80 HUs. Intensity attenuates with time at a rate of 0.7–1.5 HU/day.


Stroke radiology

142


The role of contrast head CT CT angiography .

Involves IV bolus of contrast, and imaging the arteries quickly during first pass of contrast.

.

Allows visualization of vessels or lack thereof (occlusion, stenosis, AVM, aneurysms).

.

Requirements: &

adequate renal function because the contrast bolus is more than usual;

&

.

good IV access (you don’t want contrast in soft tissues!).

CT viewing window width/level at 800/100 may be best to visualize the arteries next to bones.

Standard contrast head CT .

Allows evaluation for stroke mimics by detecting blood–brain barrier breakdown: &

Tumor, infection, inflammation, etc.

How to try to prevent contrast nephropathy .

Acetylcysteine 600 mg PO every 12 hours the day before and the day of iodinated contrast administration for CT or angiography.98,99

.

Sodium bicarbonate:100 &

154 mEq/L of sodium bicarbonate in dextrose and H2O (adding 154 mL of 1000 mEq/L sodium bicarbonate to 846 mL of 5% dextrose);

&

IV bolus at 3 mL/kg per hour 1 hour immediately

&

followed by 1 mL/kg per hour during the contrast

before radiocontrast injection (maximum 330 mL/hr); exposure and for 6 hours after the procedure (maximum 110 mL/hr).

Stroke radiology

.

Adequate hydration.

.

Creatinine >2.0 probably contraindicates use of IV contrast in most cases.

ASPECTS (Alberta Stroke Programme Early CT Score) ASPECTS is a reliable scoring system of early CT changes in MCA territory infarction in the first few hours of ischemic stroke.101 Non-contrast CT scans are interpreted at two levels: (a) at the level of basal ganglia and thalamus. (b) at the level just rostral to basal ganglia.

A

A

M4

M1 C L IC

I M5

M2

M3 M6 P

(a) at the level of basal ganglia and thalamus

P

(b) at the level just rostral to basal ganglia

ASPECTS template. Source: P. A. Barber, A. M. Demchuk, J. Zhang, & A. M. Buchan, Validity and reliability of a quantitative computed tomography score in predicting outcome of hyperacute stroke before thrombolytic therapy. ASPECTS Study Group. Alberta Stroke Programme Early CT Score. Lancet 2000; 355: 1670–4.101 Copyright # 1974, with permission from Elsevier.

143


Stroke radiology

144


ASPECTS study form 10 regions of interest At the level of basal ganglia and thalamus C ¼ caudate L ¼ lentiform nuclei IC ¼ internal capsule I ¼ insular cortex M1 ¼ anterior MCA cortex M2 ¼ MCA cortex lateral to insula M3 ¼ posterior MCA cortex

At the level just rostral to basal ganglia

M4 (superior to M1) M5 (superior to M2) M6 (superior to M3)

Notes: (Not included in scoring: A ¼ ACA circulation; P ¼ PCA circulation) Subcortical structures are allotted 3 points (C, L, and IC). MCA cortex is allotted 7 points (insular cortex, M1, M2, M3, M4, M5, and M6). 1 point is subtracted for each defined area of early ischemic change, such as focal swelling, or parenchymal hypoattenuation. The score varies from 10 to 0: . .

10 ¼ normal. 0 ¼ abnormal in entire MCA distribution.

MAGNETIC RESONANCE IMAGING (MRI) You have to refer to a real MRI book to explain all the physics of the sequences. Here is a brief simplification of what each one looks like and what they are used for.

Stroke radiology

T1-weighted sequence (usually in axial and sagittal sections)

How to identify .

Usually looks pale and bland. It looks the ‘‘most similar to CT.’’ It appears exactly how you would expect the brain to look: cerebrospinal fluid is black; gray matter is gray; white matter is white.

Use .

Good for anatomy.

.

Compare to T1 with contrast for leakage of blood–brain barrier.

T2-weighted sequence

145


Stroke radiology

146


How to identify .

Exactly the opposite of how you would expect the brain to look: cerebrospinal fluid is white; gray matter is light; white matter is dark.

Use .

Good for pathology, and to evaluate flow voids.

.

White: cerebrospinal fluid, edema, ischemia, and most bad things.

.

Dark: old blood.

FLAIR (fluid-attenuated inversion recovery)

How to identify .

Cerebrospinal fluid is dark; gray matter is light; white matter is dark.

.

It is essentially T2 with CSF made black.

Use .

Same as T2. It makes it easy to find pathology at CSF/brain junction (multiple sclerosis plaques, metastases, etc.) since on T2 it is sometimes difficult to tell what is CSF and what is pathological tissue.

Stroke radiology

.

White: edema, ischemia, and most bad things.

.

Dark: CSF, old blood.

Tips for identifying T1, T2 and FLAIR images (1) Look at CSF: (a) If it is white, it is T2. (b) If it is dark, go to step 2. (2) Look at gray and white matter: (a) If it is normal, it is T1. (b) If it is reversed, it is a FLAIR.

DWI (diffusion-weighted imaging)

How to identify .

Uniformly gray grainy image.

Use .

Shows acute ischemia.

.

White: acute ischemia (the proper term is restricted diffusion).

.

Gray: everything else.

147


Stroke radiology

148


.

With acute ischemic stroke, Na/K ATPase fails and cells swell. Intracellular H2O is less mobile than H2O in extracellular matrix. DWI is derived from the proton of the hydrogen atom.

Caution .

‘‘T2 shine-through’’ – acute ischemia should be bright on DWI, dark on ADC (see below). Sometimes when T2 whiteness is strong in an old stroke, it ‘‘shines through’’ into DWI sequences. That’s not acute stroke.

.

Artifacts at air/bone interfaces – usually occur next to temporal bone and sinuses. These artifacts are usually symmetric and can be identified.

.

Things not stroke – it turns out that many non-stroke things can appear bright on DWI. So look carefully for T2 shinethrough and think whether the pattern is stroke-like (arterial distribution). Creutzfeldt–Jakob disease has cortical ribbons of DWI brightness. Wernicke’s encephalopathy shows restricted DWI symmetrically around the aqueduct and in mammillary bodies.

.

DWI usually indicates irreversible ischemic damage, but in the first few hours, especially if not densely white (i.e., ADC not very low), DWI abnormalities can be reversed by reperfusion.

Time course of DWI intensity .

Maximal at 40 hours.

.

Normalizes in 2 to several weeks.102

Stroke radiology

ADC (apparent diffusion coefficient)

How to identify .

Grainy image with cerebrospinal fluid white.

Use .

Companion to DWI interpretation of acute ischemia.

.

Dark on ADC in area where DWI is bright (white) is ischemia.

.

One can think of it as ‘‘raw data’’ on DWI, except that ischemia is black. One can obtain quantitative measurements in the reduction in diffusion coefficient.

Time course .

Maximal (dark) at 28 hours.

.

Pseudonormalizes at 10 days, then bright.102

149


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150


MPGR (gradient-echo sequence)

How to identify .

Grayish (it’s hard by just looking).

Use .

Hemorrhages, whether new or old, appear dark.

.

It is useful when looking for micro-hemorrhages such as those from amyloid angiopathy and cavernous malformations.

.

One cannot measure the size of the hematoma on this image since the signal is amplified and is bigger than the amount of blood.

PWI (perfusion-weighted imaging)

Stroke radiology

How to identify There are two different sequences used: .

Mean time to enhancement (MTE) measures arrival time of bolus of dye. Areas of low cerebral perfusion look brighter (more light gray).

.

Negative enhancement integral (NEI) measures cerebral blood volume (CBV). Areas of severe ischemia have reduced CBV and look dark. In mild ischemia, the vascular bed is dilated, CBV may be increased, and such regions will look bright.

Use .

PWI sequences measure cerebral blood flow.

.

Look for a so-called ‘‘mismatch’’ between the changes on DWI, which are generally considered irreversible (but see fourth Caution under DWI), and areas where there is a perfusion deficit on PWI. The areas of mismatch represent tissue at risk of infarction.

MRA (magnetic resonance angiography)

151


Stroke radiology

152


How to identify .

You see the vessels.

Use .

Arterial stenosis: signal dropout more specific than appearance of stenosis.

.

Aneurysms, vascular malformations (mostly AVM).

Caution There are a lot of artifacts in MRA images. .

It’s an artifact if there are consistent findings throughout a slice (e.g., image shifted).

.

It shows flow rather than artery size. Therefore in patent but low flow states, MRA may falsely give the impression of occlusion.

.

Some MRA sequences are flow-direction sensitive. Reversed flow may appear as absent flow.

.

MRA tends to overestimate stenosis.

Ask a well-trained person to help with interpretation. If you are really interested in extracranial anatomy, especially aortic arch and vertebral origins, order MRA with contrast and speak to MRI technicians to insure they know what you want.

MRV (magnetic resonance venography)

Stroke radiology

How to identify .

You see the veins.

Use .

Suspected venous sinus thrombosis. Suspect if hemorrhagic infarct, especially if bilateral, located high in convexity, associated with more edema than usual, or not fitting the usual arterial distribution of infarcts.

Caution .

Venous anatomy is variable. Especially troublesome is normal asymmetry of transverse sinuses. Ask for help in interpretation.

Usual sequences ordered for acute ischemic stroke patients Estimated time 40 minutes. .

Sagittal T1

.

Axial DWI

.

Axial ADC

.

Axial T1

.

Axial FLAIR

.

Axial MPGR

.

PWI (MTE and NEI)

.

Axial T1 post-contrast (if PWI is done)

.

Coronal T1 post-contrast (if PWI is done)

.

MRA circle of Willis and neck

153


Blood leaves the vascular system (extravasation) 10 HITS, but without ‘‘curtain’’ effect: medium-grade shunt.

159


Transcranial Doppler ultrasound (TCD)

160


.

Curtain effect, seen when the microbubbles are so numerous as to be no longer distinguishable separately: high-grade shunt.

With regard to the physiopathological features of the RLS, we define as: .

Permanent – a shunt detected in basal conditions.

.

Latent – a shunt detected only with Valsalva.

Appendix 7 Heparin protocol Modified from Toth and Voll, 2002.107 .

Check hematocrit, platelet count, INR, PTT at baseline (within the prior 72 hours).

.

Obtain or estimate patient’s weight (use adjusted body weight for obese patients).

.

No bolus heparin. Initial heparin infusion

.

Weight

Initial infusion

119 kg

500 units/hr ¼ 10 ml/hr 600 units/hr ¼ 12 ml/hr 700 units/hr ¼ 14 ml/hr 800 units/hr ¼ 16 ml/hr 900 units/hr ¼ 18 ml/hr 1000 units/hr ¼ 20 ml/hr 1100 units/hr ¼ 22 ml/hr 1200 units/hr ¼ 24 ml/hr 1400 units/hr ¼ 28 ml/hr

Check PTT every 6 hours after change in infusion or every 24 hours if within therapeutic range.

.

CBC every 3 days.

.

Goal PTT 55–85 seconds.


Heparin protocol

162


.

Adjustment every 6 hours.

.

Check platelet count daily. A 50% decrease may indicate heparin-induced thrombocytopenia (see Appendix 9).

Heparin infusion adjustment PTT (sec) Stop infusion Change rate of infusion Check PTT 100

30 minutes 60 minutes

" 200 units/hr " 100 units/hr No change # 100 units/hr # 150 units/hr # 250 units/hr

in 6 hours in 6 hours in 6 hours next morning in 6 hours in 6 hours

.

Call physician if PTT < 45 or > 100 seconds on two

.

If significant bleeding occurs, stop heparin and assess.

consecutive measurements, or if > 125 seconds.

Appendix 8 Insulin protocol Insulin drip Make sure that the nursing unit is capable of using insulin drip with glucose measurement every 1 hour. .

Use insulin drip if the glucose in an acute stroke patient is over 250 mg/dL.

.

Target insulin level 80–110 mg/dL. &

Check capillary glucose every 1 hour.

&

Consider insulin bolus.

&

Start insulin drip at the calculated rate using the following formula: (blood sugar – 60) 0.03 ! __units/hr IV drip.

&

Readjust glucose infusion every 1 hour using the above formula.

&

If glucose is

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